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1401.0724

Ahmet Mecit \"Ozta\c{s}

Ahmet M. \"Ozta\c{s}, Michael L. Smith

The Cosmological Constant Constrained with Union2.1 Supernovae Type Ia Data. Derivation and evaluation of several FRW and Carmeli models presenting underwhelming support for the standard model

32 pages, 2 Figures Submitted to International Journal of Theoretical Physics

10.1007/s10773-014-2061-5

astro-ph.CO

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

We derive several, detailed relationships in terms of the Friedmann, Robertson, Walker (FRW) generalization which describe the Universe during both the radiation and matter dominated epochs. We explicitly provide for the influence of radiation, rather than burying this term within the matter term. Several models allow the cosmological constant (CC) to vary with universe expansion in differing manners. We evaluate these and other popular models including the $\Lambda$CDM({standard model}), quintessence as presented by Vishwakarma, Equation of State (EoS) and the Carmeli model with data from the 580 Union2.1 supernovae type Ia collection, using several minimization routines and find models built about the CC, the $\Lambda$CDM models, fare no better than those without.

[{'version': 'v1', 'created': 'Sun, 5 Jan 2014 19:36:48 GMT'} {'version': 'v2', 'created': 'Wed, 26 Nov 2014 14:42:33 GMT'}]

2015-06-18

[array(['Öztaş', 'Ahmet M.', ''], dtype=object) array(['Smith', 'Michael L.', ''], dtype=object)]

1709.04100

Jonathan Leiner

J. C. Leiner, Joosung Oh, A. I. Kolesnikov, M. B. Stone, Manh Duc Le, E. P. Kenny, B. J. Powell, M. Mourigal, E. E. Gordon, M.-H. Whangbo, J.-W. Kim, S.-W. Cheong, Je-Geun Park

Magnetic excitations of the Cu$^{2+}$ quantum spin chain in Sr$_3$CuPtO$_6$

9 pages, 5 figures

Phys. Rev. B 97, 104426 (2018)

10.1103/PhysRevB.97.104426

cond-mat.str-el

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

We report the magnetic excitation spectrum as measured by inelastic neutron scattering for a polycrystalline sample of Sr$_3$CuPtO$_6$. Modeling the data by the 2+4 spinon contributions to the dynamical susceptibility within the chains, and with interchain coupling treated in the random phase approximation, accounts for the major features of the powder-averaged structure factor. The magnetic excitations broaden considerably as temperature is raised, persisting up to above 100 K and displaying a broad transition as previously seen in the susceptibility data. No spin gap is observed in the dispersive spin excitations at low momentum transfer, which is consistent with the gapless spinon continuum expected from the coordinate Bethe ansatz. However, the temperature dependence of the excitation spectrum gives evidence of some very weak interchain coupling.

[{'version': 'v1', 'created': 'Wed, 13 Sep 2017 01:28:53 GMT'} {'version': 'v2', 'created': 'Mon, 2 Apr 2018 06:43:25 GMT'}]

2018-04-03

[array(['Leiner', 'J. C.', ''], dtype=object) array(['Oh', 'Joosung', ''], dtype=object) array(['Kolesnikov', 'A. I.', ''], dtype=object) array(['Stone', 'M. B.', ''], dtype=object) array(['Le', 'Manh Duc', ''], dtype=object) array(['Kenny', 'E. P.', ''], dtype=object) array(['Powell', 'B. J.', ''], dtype=object) array(['Mourigal', 'M.', ''], dtype=object) array(['Gordon', 'E. E.', ''], dtype=object) array(['Whangbo', 'M. -H.', ''], dtype=object) array(['Kim', 'J. -W.', ''], dtype=object) array(['Cheong', 'S. -W.', ''], dtype=object) array(['Park', 'Je-Geun', ''], dtype=object)]

2304.03561

Praveen Sai Bere

Praveen Sai Bere and Mohammed Zafar Ali Khan

Diversity Preserving, Universal Hard Decision Decoder for Linear Block Codes

Transacton of 10 pages with 4 figures

cs.IT math.IT

http://creativecommons.org/licenses/by-nc-nd/4.0/

Hard-decision decoding does not preserve the diversity order. This results in severe performance degradation in fading channels. In contrast, soft-decision decoding preserves the diversity order at an impractical computational complexity. For a linear block code $\mathscr{C}(n,k)$ of length $n$ and dimension $k$, the complexity of soft-decision decoding is of the order of $2^k$. This paper proposes a novel hard-decision decoder named Flip decoder (FD), which preserves the diversity order. Further, the proposed Flip decoder is `universally' applicable to all linear block codes. For a code $\mathscr{C}(n,k)$, with a minimum distance ${d_{\min}}$, the proposed decoder has a complexity of the order of $2^{({d_{\min}}-1)}$. For low ${d_{\min}}$ codes, this complexity is meager compared to known soft and hard decision decoding algorithms. As it also preserves diversity, it is suitable for IoT, URLLC, WBAN, and other similar applications. Simulation results and comparisons are provided for various known codes. These simulations corroborate and emphasize the practicality of the proposed decoder.

[{'version': 'v1', 'created': 'Fri, 7 Apr 2023 09:47:24 GMT'}]

2023-04-10

[array(['Bere', 'Praveen Sai', ''], dtype=object) array(['Khan', 'Mohammed Zafar Ali', ''], dtype=object)]

2106.07613

Alexander Wagner

Alexander Wagner, Elchanan Solomon, Paul Bendich

Improving Metric Dimensionality Reduction with Distributed Topology

fixed bug in code, replaced affected figures, minor improvements observed

cs.LG math.AT

http://creativecommons.org/licenses/by-sa/4.0/

We propose a novel approach to dimensionality reduction combining techniques of metric geometry and distributed persistent homology, in the form of a gradient-descent based method called DIPOLE. DIPOLE is a dimensionality-reduction post-processing step that corrects an initial embedding by minimizing a loss functional with both a local, metric term and a global, topological term. By fixing an initial embedding method (we use Isomap), DIPOLE can also be viewed as a full dimensionality-reduction pipeline. This framework is based on the strong theoretical and computational properties of distributed persistent homology and comes with the guarantee of almost sure convergence. We observe that DIPOLE outperforms popular methods like UMAP, t-SNE, and Isomap on a number of popular datasets, both visually and in terms of precise quantitative metrics.

[{'version': 'v1', 'created': 'Mon, 14 Jun 2021 17:19:44 GMT'} {'version': 'v2', 'created': 'Fri, 3 Sep 2021 16:45:49 GMT'}]

2021-09-06

[array(['Wagner', 'Alexander', ''], dtype=object) array(['Solomon', 'Elchanan', ''], dtype=object) array(['Bendich', 'Paul', ''], dtype=object)]

cond-mat/9903262

Alain Karma

Vincent Hakim and Alain Karma

Theory of spiral wave dynamics in weakly excitable media: asymptotic reduction to a kinematic model and applications

10.1103/PhysRevE.60.5073

cond-mat.soft cond-mat.stat-mech nlin.PS patt-sol

In a weakly excitable medium, characterized by a large threshold stimulus, the free end of an isolated broken plane wave (wave tip) can either rotate (steadily or unsteadily) around a large excitable core, thereby producing a spiral pattern, or retract causing the wave to vanish at boundaries. An asymptotic analysis of spiral motion and retraction is carried out in this weakly excitable large core regime starting from the free-boundary limit of the reaction-diffusion models, valid when the excited region is delimited by a thin interface. The wave description is shown to naturally split between the tip region and a far region that are smoothly matched on an intermediate scale. This separation allows us to rigorously derive an equation of motion for the wave tip, with the large scale motion of the spiral wavefront slaved to the tip. This kinematic description provides both a physical picture and exact predictions for a wide range of wave behavior, including: (i) steady rotation (frequency and core radius), (ii) exact treatment of the meandering instability in the free-boundary limit with the prediction that the frequency of unstable motion is half the primary steady frequency (iii) drift under external actions (external field with application to axisymmetric scroll ring motion in three-dimensions, and spatial or/and time-dependent variation of excitability), and (iv) the dynamics of multi-armed spiral waves with the new prediction that steadily rotating waves with two or more arms are linearly unstable. Numerical simulations of FitzHug-Nagumo kinetics are used to test several aspects of our results. In addition, we discuss the semi-quantitative extension of this theory to finite cores and pinpoint mathematical subtleties related to the thin interface limit of singly diffusive reaction-diffusion models.

[{'version': 'v1', 'created': 'Wed, 17 Mar 1999 23:44:42 GMT'}]

2009-10-31

[array(['Hakim', 'Vincent', ''], dtype=object) array(['Karma', 'Alain', ''], dtype=object)]

math/0312095

Christian `lapinou' Haase

Christian Haase

Polar decomposition and Brion's theorem

11 pages, 6 figures. Followed suggestions by referee and restructured section 3. Accepted for publication

DUKE-CGTP-03-06

math.CO

In this note we point out the relation between Brion's formula for the lattice point generating function of a convex polytope in terms of the vertex cones [Brion1988] on the one hand, and the polar decomposition \`a la Lawrence/Varchenko [Lawrence1991, Varchenko1987] on the other. We then go on to prove a version of polar decomposition for non-simple polytopes.

[{'version': 'v1', 'created': 'Wed, 3 Dec 2003 23:22:37 GMT'} {'version': 'v2', 'created': 'Thu, 10 Jun 2004 20:54:28 GMT'}]

2007-05-23

[array(['Haase', 'Christian', ''], dtype=object)]

cond-mat/9903136

Sergio Alejandro Cannas

Daniel A. Stariolo and Sergio A. Cannas

Violation of the Fluctuation-Dissipation Theorem in a Two-Dimensional Ising Model with Dipolar Interactions

5 pages (Revtex) and 3 figures (.ps)

Phys. Rev. B 60, 3013 (1999).

10.1103/PhysRevB.60.3013

cond-mat.dis-nn

The violation of the Fluctuation-Dissipation Theorem (FDT) in a two-dimensional Ising model with both ferromagnetic exchange and antiferromagnetic dipolar interactions is established and investigated via Monte Carlo simulations. Through the computation of the autocorrelation C(t+t_w,t_w) and the integrated response (susceptibility) functions we obtain the FDT violation factor X(t+t_w,t_w) for different values of the temperature, the waiting time t_w and the quotient delta=J_0/J_d, J_0 and J_d being the strength of exchange and dipolar interactions respectively. For positive values of delta this system develops a striped phase at low temperatures, in which the non-equilibrium dynamics presents two different regimes. Our results show that such different regimes are not reflected in the FDT violation factor, where X goes always to zero for high values of t_w in the aging regime, a result that appears in domain growth processes in non-frustrated ordered systems.

[{'version': 'v1', 'created': 'Mon, 8 Mar 1999 15:05:01 GMT'}]

2009-10-31

[array(['Stariolo', 'Daniel A.', ''], dtype=object) array(['Cannas', 'Sergio A.', ''], dtype=object)]

2003.14349

S\'ergio Vinicius Monteiro Castelo Branco Xavier

S\'ergio Vinicius M. C. B. Xavier, Pedro V. P. Cunha, Lu\'is C. B. Crispino, Carlos A. R. Herdeiro

Shadows of charged rotating black holes: Kerr-Newman versus Kerr-Sen

11 pages, 11 figures, Contribution to Selected Papers of the Fifth Amazonian Symposium on Physics, v2: references added, v3: typos corrected, matches published version

Int. J Modern Phys. D 29, 2041005 (2020)

10.1142/S0218271820410059

gr-qc

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

Celebrating the centennial of its first experimental test, the theory of General Relativity (GR) has successfully and consistently passed all subsequent tests with flying colours. It is expected, however, that at certain scales new physics, in particular in the form of quantum corrections, will emerge, changing some of the predictions of GR, which is a classical theory. In this respect, black holes (BHs) are natural configurations to explore the quantum effects on strong gravitational fields. BH solutions in the low-energy effective field theory description of the heterotic string theory, which is one of the leading candidates to describe quantum gravity, have been the focus of many studies in the last three decades. The recent interest in strong gravitational lensing by BHs, in the wake of the Event Horizon Telescope observations, suggests comparing the BH lensing in both GR and heterotic string theory, in order to assess the phenomenological differences between these models. In this work, we investigate the differences in the shadows of two charged BH solutions with rotation: one arising in the context of GR, namely the Kerr-Newman solution, and the other within the context of low-energy heterotic string theory, the Kerr-Sen solution. We show and interpret, in particular, that the stringy BH always has a larger shadow, for the same physical parameters and observation conditions.

[{'version': 'v1', 'created': 'Tue, 31 Mar 2020 16:32:33 GMT'} {'version': 'v2', 'created': 'Wed, 26 Aug 2020 20:41:38 GMT'} {'version': 'v3', 'created': 'Mon, 7 Dec 2020 01:51:03 GMT'}]

2020-12-08

[array(['Xavier', 'Sérgio Vinicius M. C. B.', ''], dtype=object) array(['Cunha', 'Pedro V. P.', ''], dtype=object) array(['Crispino', 'Luís C. B.', ''], dtype=object) array(['Herdeiro', 'Carlos A. R.', ''], dtype=object)]

1106.2051

Maxence Lepers

Maxence Lepers and Olivier Dulieu (Laboratoire Aim\'e Cotton, CNRS-Univ. Paris-Sud, Orsay, France)

Long-range interactions between ultracold atoms and molecules including atomic spin-orbit

Submitted to Phys. Chem. Chem. Phys., special issue on cold molecules

Physical Chemistry Chemical Physics, vol. 13, p. 19106-19113, 2011

10.1039/C1CP21568J

physics.chem-ph physics.atom-ph quant-ph

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

We investigate theoretically the long-range electrostatic interactions between a ground-state homonuclear alkali-metal dimer and an excited alkali-metal atom taking into account its fine-structure. The interaction involves the combination of first-order quadrupole-quadrupole and second-order dipole-dipole effects. Depending on the considered species, the atomic spin-orbit may be comparable to the atom-molecule electrostatic energy and to the dimer rotational structure. Here we extend our general description in the framework of the second-order degenerate perturbation theory [M. Lepers and O. Dulieu, Eur. Phys. J. D, 2011] to various regimes induced by the magnitude of the atomic spin-orbit. A complex dynamics of the atom-molecule may take place at large distances, which may have consequences for the search for an universal model of ultracold inelastic collisions as proposed for instance in [Z. Idziaszek and P. S. Julienne, Phys. Rev. Lett. \textbf{104}, 113202 (2010)].

[{'version': 'v1', 'created': 'Fri, 10 Jun 2011 13:45:07 GMT'}]

2017-09-13

[array(['Lepers', 'Maxence', '', 'Laboratoire Aimé Cotton,\n CNRS-Univ. Paris-Sud, Orsay, France'], dtype=object) array(['Dulieu', 'Olivier', '', 'Laboratoire Aimé Cotton,\n CNRS-Univ. Paris-Sud, Orsay, France'], dtype=object) ]

2003.01811

Bing Han

Bing Han, Gopalakrishnan Srinivasan, and Kaushik Roy

RMP-SNN: Residual Membrane Potential Neuron for Enabling Deeper High-Accuracy and Low-Latency Spiking Neural Network

to be published in CVPR'20

cs.NE cs.CV cs.LG

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

Spiking Neural Networks (SNNs) have recently attracted significant research interest as the third generation of artificial neural networks that can enable low-power event-driven data analytics. The best performing SNNs for image recognition tasks are obtained by converting a trained Analog Neural Network (ANN), consisting of Rectified Linear Units (ReLU), to SNN composed of integrate-and-fire neurons with "proper" firing thresholds. The converted SNNs typically incur loss in accuracy compared to that provided by the original ANN and require sizable number of inference time-steps to achieve the best accuracy. We find that performance degradation in the converted SNN stems from using "hard reset" spiking neuron that is driven to fixed reset potential once its membrane potential exceeds the firing threshold, leading to information loss during SNN inference. We propose ANN-SNN conversion using "soft reset" spiking neuron model, referred to as Residual Membrane Potential (RMP) spiking neuron, which retains the "residual" membrane potential above threshold at the firing instants. We demonstrate near loss-less ANN-SNN conversion using RMP neurons for VGG-16, ResNet-20, and ResNet-34 SNNs on challenging datasets including CIFAR-10 (93.63% top-1), CIFAR-100 (70.93% top-1), and ImageNet (73.09% top-1 accuracy). Our results also show that RMP-SNN surpasses the best inference accuracy provided by the converted SNN with "hard reset" spiking neurons using 2-8 times fewer inference time-steps across network architectures and datasets.

[{'version': 'v1', 'created': 'Tue, 25 Feb 2020 18:19:12 GMT'} {'version': 'v2', 'created': 'Wed, 1 Apr 2020 17:27:05 GMT'}]

2020-04-02

[array(['Han', 'Bing', ''], dtype=object) array(['Srinivasan', 'Gopalakrishnan', ''], dtype=object) array(['Roy', 'Kaushik', ''], dtype=object)]

1206.1642

Luisa Jaime

Luisa G. Jaime, Leonardo Patino and Marcelo Salgado

f(R) Cosmology revisited

35 pages; 33 figures; revtex

gr-qc astro-ph.CO hep-th

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

We consider a class of metric f(R) modified gravity theories, analyze them in the context of a Friedmann-Robertson-Walker cosmology and confront the results with some of the known constraints imposed by observations. In particular, we focus in correctly reproducing the matter and effective cosmological constant eras, the age of the Universe, and supernovae data. Our analysis differs in many respects from previous studies. First, we avoid any transformation to a scalar-tensor theory in order to be exempted of any potential pathologies (e.g. multivalued scalar potentials) and also to evade any unnecessary discussion regarding frames (i.e. Einstein vs Jordan). Second, based on a robust approach, we recast the cosmology equations as an initial value problem subject to a modified Hamiltonian constraint. Third, we solve the equations numerically where the Ricci scalar itself is one of the variables, and use the constraint equation to monitor the accuracy of the solutions. We compute the "equation of state" (EOS) associated with the modifications of gravity using several inequivalent definitions that have been proposed in the past and analyze it in detail. We argue that one of these definitions has the best features. In particular, we present the EOS around the so called "phantom divide" boundary and compare it with previous findings.

[{'version': 'v1', 'created': 'Thu, 7 Jun 2012 23:56:07 GMT'}]

2012-06-11

[array(['Jaime', 'Luisa G.', ''], dtype=object) array(['Patino', 'Leonardo', ''], dtype=object) array(['Salgado', 'Marcelo', ''], dtype=object)]

1204.5655

Anna Melbinger

Anna Melbinger, Louis Reese, Erwin Frey

Microtubule Length-Regulation by Molecular Motors

7 pages (5 p. letter, 3 p. supplementary information), 4 figures (3 f. letter, 1 f. supplementary information)

Phys. Rev. Lett. 108, 258104 (2012)

10.1103/PhysRevLett.108.258104

LMU-ASC 14/12

q-bio.SC cond-mat.stat-mech physics.bio-ph

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

Length-regulation of microtubules (MTs) is essential for many cellular processes. Molecular motors like kinesin 8, which move along MTs and also act as depolymerases, are known as key players in MT dynamics. However, the regulatory mechanisms of length control remain elusive. Here, we investigate a stochastic model accounting for the interplay between polymerization kinetics and motor-induced depolymerization. We determine the dependence of MT length and variance on rate constants and motor concentration. Moreover, our analyses reveal how collective phenomena lead to a well-defined MT length.

[{'version': 'v1', 'created': 'Wed, 25 Apr 2012 13:40:49 GMT'}]

2012-10-18

[array(['Melbinger', 'Anna', ''], dtype=object) array(['Reese', 'Louis', ''], dtype=object) array(['Frey', 'Erwin', ''], dtype=object)]

2207.06141

Xueyuan Wan

Xiaoxiang Chai, Xueyuan Wan

The mass of an asymptotically hyperbolic end and distance estimates

24 pages, 3 figures

10.1063/5.0121452

math.DG math-ph math.MP

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

Let $(M,g)$ be a complete connected $n$-dimensional Riemannian spin manifold without boundary such that the scalar curvature satisfies $R_g\geq -n(n-1)$ and $\mathcal{E}\subset M$ be an asymptotically hyperbolic end, we prove that the mass functional of the end $\mathcal{E}$ is timelike future-directed or zero. Moreover, it vanishes if and only if $(M,g)$ is isometric to the hyperbolic space. We also consider the mass of an asymptotically hyperbolic manifold with compact boundary, we prove the mass is timelike future-directed if the mean curvature of the boundary is bounded from below by a function defined using distance estimates. As an application, the mass is timelike future-directed if the mean curvature of the boundary is bounded from below by $-(n-1)$ or the scalar curvature satisfies $R_g\geq (-1+\kappa)n(n-1)$ for any positive constant $\kappa$ less than one.

[{'version': 'v1', 'created': 'Wed, 13 Jul 2022 12:04:17 GMT'}]

2022-12-28

[array(['Chai', 'Xiaoxiang', ''], dtype=object) array(['Wan', 'Xueyuan', ''], dtype=object)]

0906.3541

Javier Fernandez-Rodriguez

J. Fernandez-Rodriguez, V. Scagnoli, C. Mazzoli, F. Fabrizi, S.W. Lovesey, J. A. Blanco, D.S. Sivia, K.S. Knight, F. de Bergevin, L. Paolasini

Experimental evidence of anapolar moments in the antiferromagnetic insulating phase of V2O3 obtained from x-ray resonant Bragg diffraction

Phys. Rev. B 81, 085107 (2010)

10.1103/PhysRevB.81.085107

cond-mat.str-el

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

We have investigated the antiferromagnetic insulating phase of the Mott-Hubbard insulator V$_2$O$_3$ by resonant x-ray Bragg diffraction at the vanadium K-edge. Combining the information obtained from azimuthal angle scans, linear incoming polarization scans and by fitting collected data to the scattering amplitude derived from the established chemical I2/a and magnetic space groups we provide evidence of the ordering motif of anapolar moments (which results from parity violation coupling to an electromagnetic field). Experimental data (azimuthal dependence and polarization analysis) collected at space-group forbidden Bragg reflections are successfully accounted within our model in terms of vanadium magnetoelectric multipoles. We demonstrate that resonant x-ray diffraction intensities in all space-group forbidden Bragg reflections of the kind $(hkl)_m$ with odd $h$ are produced by an E1-E2 event. The determined tensorial parameters offer a test for ab-initio calculations in this material, that can lead to a deeper and more quantitative understanding of the physical properties of V$_2$O$_3$.

[{'version': 'v1', 'created': 'Thu, 18 Jun 2009 22:11:23 GMT'}]

2014-05-22

[array(['Fernandez-Rodriguez', 'J.', ''], dtype=object) array(['Scagnoli', 'V.', ''], dtype=object) array(['Mazzoli', 'C.', ''], dtype=object) array(['Fabrizi', 'F.', ''], dtype=object) array(['Lovesey', 'S. W.', ''], dtype=object) array(['Blanco', 'J. A.', ''], dtype=object) array(['Sivia', 'D. S.', ''], dtype=object) array(['Knight', 'K. S.', ''], dtype=object) array(['de Bergevin', 'F.', ''], dtype=object) array(['Paolasini', 'L.', ''], dtype=object)]

astro-ph/0204179

Steven Sembay

S. Sembay (1), R. Edelson (1 and 2), A. Markowitz (2), R. G. Griffiths (1) and M. J. L. Turner (1) ((1) Leicester University, UK, (2) UCLA, USA)

Complex X-ray spectral variability in Mkn 421 observed with XMM-Newton

21 pages, 4 figures, accepted for ApJ, scheduled for August 1, 2002

10.1086/341108

astro-ph

The bright blazar Mkn 421 has been observed four times for uninterrupted durations of ~ 9 - 13 hr during the performance verification and calibration phases of the XMM-Newton mission. The source was strongly variable in all epochs, with variability amplitudes that generally increased to higher energy bands. Although the detailed relationship between soft (0.1 - 0.75 keV) and hard (2 - 10 keV) band differed from one epoch to the next, in no case was there any evidence for a measurable interband lag, with robust upper limits of $| \tau | < 0.08 $ hr in the best-correlated light curves. This is in conflict with previous claims of both hard and soft lags of ~1 hr in this and other blazars. However, previous observations suffered a repeated 1.6 hr feature induced by the low-Earth orbital period, a feature that is not present in the uninterrupted XMM-Newton data. The new upper limit on $|\tau|$ leads to a lower limit on the magnetic field strength and Doppler factor of $ B \delta^{1/3} \gs 4.7 $ G, mildly out of line with the predictions from a variety of homogeneous synchrotron self-Compton emission models in the literature of $ B \delta^{1/3} = 0.2 - 0.8 $ G. Time-dependent spectral fitting was performed on all epochs, and no detectable spectral hysteresis was seen. We note however that the source exhibited significantly different spectral evolutionary behavior from one epoch to the next, with the strongest correlations in the first and last and an actual divergance between soft and hard X-ray bands in the third. This indicates that the range of spectral variability behavior in Mkn 421 is not fully described in these short snippets; significantly longer uninterrupted light curves are required, and can be obtained with XMM-Newton.

[{'version': 'v1', 'created': 'Wed, 10 Apr 2002 15:18:11 GMT'}]

2009-11-07

[array(['Sembay', 'S.', '', 'Leicester University, UK'], dtype=object) array(['Edelson', 'R.', '', '1 and 2'], dtype=object) array(['Markowitz', 'A.', '', 'UCLA, USA'], dtype=object) array(['Griffiths', 'R. G.', '', 'Leicester University, UK'], dtype=object) array(['Turner', 'M. J. L.', '', 'Leicester University, UK'], dtype=object)]

1909.12114

Leila Arras

Leila Arras, Jose A. Arjona-Medina, Michael Widrich, Gr\'egoire Montavon, Michael Gillhofer, Klaus-Robert M\"uller, Sepp Hochreiter and Wojciech Samek

Explaining and Interpreting LSTMs

28 pages, 7 figures, book chapter, In: Explainable AI: Interpreting, Explaining and Visualizing Deep Learning, LNCS volume 11700, Springer 2019. arXiv admin note: text overlap with arXiv:1806.07857

10.1007/978-3-030-28954-6_11

cs.LG cs.NE stat.ML

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

While neural networks have acted as a strong unifying force in the design of modern AI systems, the neural network architectures themselves remain highly heterogeneous due to the variety of tasks to be solved. In this chapter, we explore how to adapt the Layer-wise Relevance Propagation (LRP) technique used for explaining the predictions of feed-forward networks to the LSTM architecture used for sequential data modeling and forecasting. The special accumulators and gated interactions present in the LSTM require both a new propagation scheme and an extension of the underlying theoretical framework to deliver faithful explanations.

[{'version': 'v1', 'created': 'Wed, 25 Sep 2019 11:45:43 GMT'}]

2019-09-27

[array(['Arras', 'Leila', ''], dtype=object) array(['Arjona-Medina', 'Jose A.', ''], dtype=object) array(['Widrich', 'Michael', ''], dtype=object) array(['Montavon', 'Grégoire', ''], dtype=object) array(['Gillhofer', 'Michael', ''], dtype=object) array(['Müller', 'Klaus-Robert', ''], dtype=object) array(['Hochreiter', 'Sepp', ''], dtype=object) array(['Samek', 'Wojciech', ''], dtype=object)]

2101.08725

Elvira Di Nardo Prof.

E. Di Nardo, D. Senato

Symbolic solutions of some linear recurrences

arXiv admin note: text overlap with arXiv:0810.3554

Jour. Statist. Plann. Inference (2012), 142(2), 423--429

10.1016/j.jspi.2011.07.022

math.CO

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

A symbolic method for solving linear recurrences of combinatorial and statistical interest is introduced. This method essentially relies on a representation of polynomial sequences as moments of a symbol that looks as the framework of a random variable with no reference to any probability space. We give several examples of applications and state an explicit form for the class of linear recurrences involving Sheffer sequences satisfying a special initial condition. The results here presented can be easily implemented in a symbolic software.

[{'version': 'v1', 'created': 'Thu, 21 Jan 2021 17:06:34 GMT'}]

2021-01-22

[array(['Di Nardo', 'E.', ''], dtype=object) array(['Senato', 'D.', ''], dtype=object)]

1608.07288

Matthew Taylor

Matthew A. Taylor, Thomas H. Puzia, Roberto P. Mu\~noz, Steffen Mieske, Ariane Lan\c{c}on, Hongxin Zhang, Paul Eigenthaler, and Mia Sauda Bovill

The Survey of Centaurus A's Baryonic Structures (SCABS). II. The Extended Globular Cluster System of NGC5128 and its Nearby Environment

26 pages, 15 figures, 9 tables; revised version accepted to MNRAS

10.1093/mnras/stx1021

astro-ph.GA

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

Wide-field $u'g'r'i'z'$ Dark Energy Camera observations centred on the giant elliptical galaxy NGC5128 covering $\sim21deg^2$ are used to compile a new catalogue of $\sim3200$ globular clusters (GCs). We report 2404 new candidates, including the vast majority within $\sim140$kpc of NGC5128. We find evidence for a transition at a galactocentric radius of $R_{\rm gc}\approx55$kpc from GCs intrinsic to NGC5128 to those likely to have been accreted from dwarf galaxies or that may transition to the intra-group medium of the Centaurus A galaxy group. We fit power-law surface number density profiles of the form $\Sigma_{N, R_{\rm gc}}\propto R_{\rm gc}^\Gamma$ and find that inside the transition radius, the red GCs are more centrally concentrated than the blue, with $\Gamma_{\rm inner,red}\approx-1.78$ and $\Gamma_{\rm inner,blue}\approx-1.40$. Outside this region both profiles flatten, more dramatically for the red GCs ($\Gamma_{\rm outer,red}\approx-0.33$) compared to the blue ($\Gamma_{\rm outer,blue}\approx-0.61$), although the former is more likely to suffer contamination by background sources. The median $(g'\!-\!z')_0\!=\!1.27$mag colour of the inner red population is consistent with arising from the amalgamation of two giant galaxies each less luminous than present-day NGC5128. Both in- and out-ward of the transition radius, we find the fraction of blue GCs to dominate over the red GCs, indicating a lively history of minor-mergers. Assuming the blue GCs to originate primarily in dwarf galaxies, we model the population required to explain them, while remaining consistent with NGC5128's present-day spheroid luminosity. We find that several dozen dwarfs of luminosities $L_{dw,V}\simeq10^{6-9.3}L_{V,\odot}$, following a Schechter luminosity function with a faint-end slope of $-1.50\leq\alpha\leq-1.25$ is favoured, many of which may have already been disrupted in NGC5128's tidal field.

[{'version': 'v1', 'created': 'Thu, 25 Aug 2016 20:00:06 GMT'} {'version': 'v2', 'created': 'Fri, 28 Apr 2017 18:00:08 GMT'}]

2017-06-21

[array(['Taylor', 'Matthew A.', ''], dtype=object) array(['Puzia', 'Thomas H.', ''], dtype=object) array(['Muñoz', 'Roberto P.', ''], dtype=object) array(['Mieske', 'Steffen', ''], dtype=object) array(['Lançon', 'Ariane', ''], dtype=object) array(['Zhang', 'Hongxin', ''], dtype=object) array(['Eigenthaler', 'Paul', ''], dtype=object) array(['Bovill', 'Mia Sauda', ''], dtype=object)]

2210.14598

Martin Magris

Martin Magris, Mostafa Shabani, Alexandros Iosifidis

Exact Manifold Gaussian Variational Bayes

stat.ML cs.LG

http://creativecommons.org/licenses/by/4.0/

We propose an optimization algorithm for Variational Inference (VI) in complex models. Our approach relies on natural gradient updates where the variational space is a Riemann manifold. We develop an efficient algorithm for Gaussian Variational Inference that implicitly satisfies the positive definite constraint on the variational covariance matrix. Our Exact manifold Gaussian Variational Bayes (EMGVB) provides exact but simple update rules and is straightforward to implement. Due to its black-box nature, EMGVB stands as a ready-to-use solution for VI in complex models. Over five datasets, we empirically validate our feasible approach on different statistical, econometric, and deep learning models, discussing its performance with respect to baseline methods.

[{'version': 'v1', 'created': 'Wed, 26 Oct 2022 10:12:31 GMT'}]

2022-10-27

[array(['Magris', 'Martin', ''], dtype=object) array(['Shabani', 'Mostafa', ''], dtype=object) array(['Iosifidis', 'Alexandros', ''], dtype=object)]

1508.05658

Joel Giedt

Dean Howarth, Joel Giedt

The sigma meson from lattice QCD with two-pion interpolating operators

1+21 pages, 3 figures, various improvements to discussion, added explanatory appendices

hep-lat hep-ph nucl-th

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

In this article we describe our studies of the sigma meson, f_0(500), using two-pion correlation functions. We use lattice quantum chromodynamics in the quenched approximation with so-called clover fermions. By working at unphysical pion masses we are able to identify a would-be resonance with mass less than $2 m_\pi$, and then extrapolate to the physical point. We include the most important annihilation diagram, which is "partially disconnnected" or "single annihilation." Because this diagram is quite expensive to compute, we introduce a somewhat novel technique for the computation of all-to-all diagrams, based on momentum sources and a truncation in momentum space. In practice, we use only ${\bf p}=0$ modes, so the method reduces to wall sources. At the point where the mass of the pion takes its physical value, we find a resonance in the $0^{++}$ two-pion channel with a mass of approximately $609 \pm 80$ MeV, consistent with the expected properties of the sigma meson, given the approximations we are making.

[{'version': 'v1', 'created': 'Sun, 23 Aug 2015 20:43:26 GMT'} {'version': 'v2', 'created': 'Tue, 22 Aug 2017 16:55:58 GMT'}]

2017-08-23

[array(['Howarth', 'Dean', ''], dtype=object) array(['Giedt', 'Joel', ''], dtype=object)]

2204.12408

Yuying Ge

Yuying Ge, Yixiao Ge, Xihui Liu, Alex Jinpeng Wang, Jianping Wu, Ying Shan, Xiaohu Qie and Ping Luo

MILES: Visual BERT Pre-training with Injected Language Semantics for Video-text Retrieval

cs.CV

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

Dominant pre-training work for video-text retrieval mainly adopt the "dual-encoder" architectures to enable efficient retrieval, where two separate encoders are used to contrast global video and text representations, but ignore detailed local semantics. The recent success of image BERT pre-training with masked visual modeling that promotes the learning of local visual context, motivates a possible solution to address the above limitation. In this work, we for the first time investigate masked visual modeling in video-text pre-training with the "dual-encoder" architecture. We perform Masked visual modeling with Injected LanguagE Semantics (MILES) by employing an extra snapshot video encoder as an evolving "tokenizer" to produce reconstruction targets for masked video patch prediction. Given the corrupted video, the video encoder is trained to recover text-aligned features of the masked patches via reasoning with the visible regions along the spatial and temporal dimensions, which enhances the discriminativeness of local visual features and the fine-grained cross-modality alignment. Our method outperforms state-of-the-art methods for text-to-video retrieval on four datasets with both zero-shot and fine-tune evaluation protocols. Our approach also surpasses the baseline models significantly on zero-shot action recognition, which can be cast as video-to-text retrieval.

[{'version': 'v1', 'created': 'Tue, 26 Apr 2022 16:06:31 GMT'}]

2022-04-27

[array(['Ge', 'Yuying', ''], dtype=object) array(['Ge', 'Yixiao', ''], dtype=object) array(['Liu', 'Xihui', ''], dtype=object) array(['Wang', 'Alex Jinpeng', ''], dtype=object) array(['Wu', 'Jianping', ''], dtype=object) array(['Shan', 'Ying', ''], dtype=object) array(['Qie', 'Xiaohu', ''], dtype=object) array(['Luo', 'Ping', ''], dtype=object)]

1911.06962

Komal Teru

Komal K. Teru, Etienne Denis, William L. Hamilton

Inductive Relation Prediction by Subgraph Reasoning

cs.LG cs.AI stat.ML

http://creativecommons.org/licenses/by/4.0/

The dominant paradigm for relation prediction in knowledge graphs involves learning and operating on latent representations (i.e., embeddings) of entities and relations. However, these embedding-based methods do not explicitly capture the compositional logical rules underlying the knowledge graph, and they are limited to the transductive setting, where the full set of entities must be known during training. Here, we propose a graph neural network based relation prediction framework, GraIL, that reasons over local subgraph structures and has a strong inductive bias to learn entity-independent relational semantics. Unlike embedding-based models, GraIL is naturally inductive and can generalize to unseen entities and graphs after training. We provide theoretical proof and strong empirical evidence that GraIL can represent a useful subset of first-order logic and show that GraIL outperforms existing rule-induction baselines in the inductive setting. We also demonstrate significant gains obtained by ensembling GraIL with various knowledge graph embedding methods in the transductive setting, highlighting the complementary inductive bias of our method.

[{'version': 'v1', 'created': 'Sat, 16 Nov 2019 05:25:56 GMT'} {'version': 'v2', 'created': 'Wed, 12 Feb 2020 02:16:11 GMT'}]

2020-02-13

[array(['Teru', 'Komal K.', ''], dtype=object) array(['Denis', 'Etienne', ''], dtype=object) array(['Hamilton', 'William L.', ''], dtype=object)]

1901.04354

Ravi Ramakrishna

Farshid Hajir, Christian Maire, Ravi Ramakrishna

Cutting towers of number fields

math.NT

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

Given a prime $p$, a number field $\K$ and a finite set of places $S$ of $\K$, let $\K_S$ be the maximal pro-$p$ extension of $\K$ unramified outside $S$. Using the Golod-Shafarevich criterion one can often show that $\K_S/\K$ is infinite. In both the tame and wild cases we construct infinite subextensions with bounded ramification using the refined Golod-Shafarevich criterion. In the tame setting we achieve new records on Martinet constants (root discriminant bounds) in the totally real and totally complex cases. We are also able to answer a question of Ihara by producing infinite asymptotically good extensions in which infinitely many primes split completely.

[{'version': 'v1', 'created': 'Mon, 14 Jan 2019 14:58:44 GMT'}]

2019-01-15

[array(['Hajir', 'Farshid', ''], dtype=object) array(['Maire', 'Christian', ''], dtype=object) array(['Ramakrishna', 'Ravi', ''], dtype=object)]

0901.4891

Choukrallah Reda

Gilles Cassier, Reda Choukrallah

Resultats de cyclicite pour des operateurs de Toeplitz anti-analytiques

This paper has been withdrawn by the authors due to publication of an improved version in Extracta Mathematicae Vol. 27, N?um. 1, 31-58 (2012) under the title "Cyclicity Results for Some Antianalytic Toeplitz Operators Acting on Hp"

math.CV

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

Le but de cet article est d'obtenir la cyclicite de certaines classes de fonctions pour des operateurs de Toeplitz anti-analytique associes a un produit fini de Blaschke dans les espaces $H^p$ ou $1<p<\infty$. Il s'agit aussi de decrire les sous-espaces invariants par ce type d'operateur et engendres par des decompositions lacunaires de fonctions.

[{'version': 'v1', 'created': 'Fri, 30 Jan 2009 14:11:07 GMT'} {'version': 'v2', 'created': 'Thu, 31 Jan 2013 03:09:16 GMT'}]

2013-02-01

[array(['Cassier', 'Gilles', ''], dtype=object) array(['Choukrallah', 'Reda', ''], dtype=object)]

1110.4014

Sarah Mason

Sarah Mason and Jeffrey Remmel

Row-strict quasisymmetric Schur functions

17 pages, 11 figures

math.CO

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

Haglund, Luoto, Mason, and van Willigenburg introduced a basis for quasisymmetric functions called the quasisymmetric Schur function basis, generated combinatorially through fillings of composition diagrams in much the same way as Schur functions are generated through reverse column-strict tableaux. We introduce a new basis for quasisymmetric functions called the row-strict quasisymmetric Schur function basis, generated combinatorially through fillings of composition diagrams in much the same way as Schur functions are generated through row-strict tableaux. We describe the relationship between this new basis and other known bases for quasisymmetric functions, as well as its relationship to Schur polynomials. We obtain a refinement of the omega transform operator as a result of these relationships.

[{'version': 'v1', 'created': 'Tue, 18 Oct 2011 15:07:06 GMT'}]

2011-10-19

[array(['Mason', 'Sarah', ''], dtype=object) array(['Remmel', 'Jeffrey', ''], dtype=object)]

2004.09762

Shaosai Huang

Shaosai Huang, Bing Wang

Rigidity of the first Betti number via Ricci flow smoothing

41 pages, 3 figures. References added

math.DG

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

The Colding-Gromov gap theorem asserts that an almost non-negatively Ricci curved manifold with unit diameter and maximal first Betti number is homeomorphic to the flat torus. In this paper, we prove a parametrized version of this theorem, in the context of collapsing Riemannian manifolds with Ricci curvature bounded below: if a closed manifold with Ricci curvature uniformly bounded below is Gromov-Hausdorff close to a (lower dimensional) manifold with bounded geometry, and has the difference of their first Betti numbers equal to the dimensional difference, then it is diffeomorphic to a torus bundle over the one with bounded geometry. We rely on two novel technical tools: the first is an effective control of the spreading of minimal geodesics with initial data parallel transported along a short geodesic segment, and the second is a Ricci flow smoothing result for certain collapsing initial data with Ricci curvature bounded below.

[{'version': 'v1', 'created': 'Tue, 21 Apr 2020 05:43:11 GMT'} {'version': 'v2', 'created': 'Tue, 8 Jun 2021 23:44:10 GMT'}]

2021-06-10

[array(['Huang', 'Shaosai', ''], dtype=object) array(['Wang', 'Bing', ''], dtype=object)]

2204.03375

Suvodip Dey

Suvodip Dey, Ramamohan Kummara, Maunendra Sankar Desarkar

Towards Fair Evaluation of Dialogue State Tracking by Flexible Incorporation of Turn-level Performances

ACL 2022 Main Conference (short paper)

cs.CL

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

Dialogue State Tracking (DST) is primarily evaluated using Joint Goal Accuracy (JGA) defined as the fraction of turns where the ground-truth dialogue state exactly matches the prediction. Generally in DST, the dialogue state or belief state for a given turn contains all the intents shown by the user till that turn. Due to this cumulative nature of the belief state, it is difficult to get a correct prediction once a misprediction has occurred. Thus, although being a useful metric, it can be harsh at times and underestimate the true potential of a DST model. Moreover, an improvement in JGA can sometimes decrease the performance of turn-level or non-cumulative belief state prediction due to inconsistency in annotations. So, using JGA as the only metric for model selection may not be ideal for all scenarios. In this work, we discuss various evaluation metrics used for DST along with their shortcomings. To address the existing issues, we propose a new evaluation metric named Flexible Goal Accuracy (FGA). FGA is a generalized version of JGA. But unlike JGA, it tries to give penalized rewards to mispredictions that are locally correct i.e. the root cause of the error is an earlier turn. By doing so, FGA considers the performance of both cumulative and turn-level prediction flexibly and provides a better insight than the existing metrics. We also show that FGA is a better discriminator of DST model performance.

[{'version': 'v1', 'created': 'Thu, 7 Apr 2022 11:52:11 GMT'}]

2022-04-08

[array(['Dey', 'Suvodip', ''], dtype=object) array(['Kummara', 'Ramamohan', ''], dtype=object) array(['Desarkar', 'Maunendra Sankar', ''], dtype=object)]

math/0610303

Zach Teitler

Zach Teitler

A note on Mustata's computation of multiplier ideals of hyperplane arrangements

5 pages; comments welcome

Proc. Amer. Math. Soc. 136 (2008), no. 5, 1575--1579

10.1090/S0002-9939-07-09177-0

math.AG

M. Mustata used jet schemes to compute the multiplier ideals of reduced hyperplane arrangements. We give an alternate proof using a log resolution, which is simpler and allows us to consider non-reduced arrangements. By applying the idea of wonderful models introduced by De Concini--Procesi, we also simplify the result.

[{'version': 'v1', 'created': 'Mon, 9 Oct 2006 22:49:33 GMT'} {'version': 'v2', 'created': 'Sat, 17 Mar 2007 15:19:49 GMT'}]

2011-07-11

[array(['Teitler', 'Zach', ''], dtype=object)]

2306.01144

Victoria Helus

Nathan Vaska, Victoria Helus

Evaluating the Capabilities of Multi-modal Reasoning Models with Synthetic Task Data

cs.LG cs.CL

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

The impressive advances and applications of large language and joint language-and-visual understanding models has led to an increased need for methods of probing their potential reasoning capabilities. However, the difficulty of gather naturally-occurring data for complex multi-modal reasoning tasks bottlenecks the evaluation of AI methods on tasks which are not already covered by an academic dataset. In this work, we leverage recent advances in high resolution text-to-image generation to develop a framework for generating evaluation data for multi-modal reasoning tasks. We apply this framework to generate context-dependent anomaly data, creating a synthetic dataset on a challenging task which is not well covered by existing datasets. We benchmark the performance of a state-of-the-art visual question answering (VQA) model against data generated with this method, and demonstrate that while the task is tractable, the model performs significantly worse on the context-dependent anomaly detection task than on standard VQA tasks.

[{'version': 'v1', 'created': 'Thu, 1 Jun 2023 20:56:34 GMT'}]

2023-06-05

[array(['Vaska', 'Nathan', ''], dtype=object) array(['Helus', 'Victoria', ''], dtype=object)]

1403.7052

Sheng Zhang

Sheng Zhang

Analysis of a discontinuous Galerkin method for Koiter shell

math.NA

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

We present an analysis for a mixed finite element method for the bending problem of Koiter shell. We derive an error estimate showing that when the geometrical coefficients of the shell mid-surface satisfy certain conditions the finite element method has the optimal order of accuracy, which is uniform with respect to the shell thickness. Generally, the error estimate shows how the accuracy is affected by the shell geometry and thickness. It suggests that to achieve optimal rate of convergence, the triangulation should be properly refined in regions where the shell geometry changes dramatically. The analysis is carried out for a balanced method in which the normal component of displacement is approximated by discontinuous piecewise cubic polynomials, while the tangential components are approximated by discontinuous piecewise quadratic polynomials, with some enrichment on elements that have edges on the free boundary. Components of the membrane stress are approximated by continuous piecewise linear functions.

[{'version': 'v1', 'created': 'Thu, 27 Mar 2014 14:28:09 GMT'}]

2014-03-28

[array(['Zhang', 'Sheng', ''], dtype=object)]

2211.10505

Thomas Barthelm\'e

Thomas Barthelm\'e, Steven Frankel, Kathryn Mann

Orbit equivalences of pseudo-Anosov flows

52 pages, 24 figures, comments welcome

math.DS math.GT

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

We prove a classification theorem for transitive Anosov and pseudo-Anosov flows on closed 3-manifolds, up to orbit equivalence. In many cases, flows on a 3-manifold $M$ are completely determined by the set of free homotopy classes of their (unoriented) periodic orbits. The exceptional cases are flows with a special structure in their orbit space called a ``tree of scalloped regions"; in these cases the set of free homotopy classes of unoriented periodic orbits together with the additional data of a choice of sign for each $\pi_1(M)$-orbit of tree gives a complete invariant of orbit equivalence classes of flows. The framework for the proof is a more general result about \emph{Anosov-like actions} of abstract groups on bifoliated planes, showing that the homeomorphism type of the bifoliation and the conjugacy class of the action can be recovered from knowledge of which elements of the group act with fixed points. As a consequence, we show that Anosov flows are determined up to orbit equivalence by the action on the ideal boundary of their orbit spaces, and more generally that transitive Anosov-like actions on bifoliated planes are determined up to conjugacy by their actions on the plane's ideal boundary: any conjugacy between two such actions on their ideal circles can be extended uniquely to a conjugacy on the interior of the plane.

[{'version': 'v1', 'created': 'Fri, 18 Nov 2022 20:35:42 GMT'}]

2022-11-22

[array(['Barthelmé', 'Thomas', ''], dtype=object) array(['Frankel', 'Steven', ''], dtype=object) array(['Mann', 'Kathryn', ''], dtype=object)]

1311.6214

Yoichi Ikeda

Yoichi Ikeda (Nishina Ctr. RIKEN), Bruno Charron (Univ. Tokyo), Sinya Aoki (Kyoto U., YITP), Takumi Doi (Nishina Ctr. RIKEN), Tetsuo Hatsuda (Nishina Ctr. RIKEN & Univ. Tokyo, IPMU), Takashi Inoue (Nihon U.), Noriyoshi Ishii (Univ. Tsukuba), Keiko Murano (Kyoto U., YITP), Hidekatsu Nemura (Univ. Tsukuba), Kenji Sasaki (Univ. Tsukuba) (HAL QCD Collaboration)

Charmed Tetraquarks Tcc and Tcs from Dynamical Lattice QCD Simulations

15 pages, 4 figures

10.1016/j.physletb.2014.01.002

RIKEN-QHP-105, YITP-13-119

hep-lat hep-ph nucl-th

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

Charmed tetraquarks $T_{cc}=(cc\bar{u}\bar{d})$ and $T_{cs}=(cs\bar{u}\bar{d})$ are studied through the S-wave meson-meson interactions, $D$-$D$, $\bar{K}$-$D$, $D$-$D^{*}$ and $\bar{K}$-$D^{*}$, on the basis of the (2+1)-flavor lattice QCD simulations with the pion mass $m_{\pi} \simeq $410, 570 and 700 MeV. For the charm quark, the relativistic heavy quark action is employed to treat its dynamics on the lattice. Using the HAL QCD method, we extract the S-wave potentials in lattice QCD simulations, from which the meson-meson scattering phase shifts are calculated. The phase shifts in the isospin triplet ($I$=1) channels indicate repulsive interactions, while those in the $I=0$ channels suggest attraction, growing as $m_{\pi}$ decreases. This is particularly prominent in the $T_{cc} (J^P=1^+,I=0)$ channel, though neither bound state nor resonance are found in the range $m_{\pi} =410-700$ MeV. We make a qualitative comparison of our results with the phenomenological diquark picture.

[{'version': 'v1', 'created': 'Mon, 25 Nov 2013 05:56:00 GMT'} {'version': 'v2', 'created': 'Fri, 10 Jan 2014 07:28:05 GMT'}]

2014-01-13

[array(['Ikeda', 'Yoichi', '', 'Nishina Ctr. RIKEN'], dtype=object) array(['Charron', 'Bruno', '', 'Univ. Tokyo'], dtype=object) array(['Aoki', 'Sinya', '', 'Kyoto U., YITP'], dtype=object) array(['Doi', 'Takumi', '', 'Nishina Ctr. RIKEN'], dtype=object) array(['Hatsuda', 'Tetsuo', '', 'Nishina Ctr. RIKEN & Univ. Tokyo, IPMU'], dtype=object) array(['Inoue', 'Takashi', '', 'Nihon U.'], dtype=object) array(['Ishii', 'Noriyoshi', '', 'Univ. Tsukuba'], dtype=object) array(['Murano', 'Keiko', '', 'Kyoto U., YITP'], dtype=object) array(['Nemura', 'Hidekatsu', '', 'Univ.\n Tsukuba'], dtype=object) array(['Sasaki', 'Kenji', '', 'Univ. Tsukuba'], dtype=object)]

2107.05412

Matteo Caorsi

Juli\'an Burella P\'erez, Sydney Hauke, Umberto Lupo, Matteo Caorsi, Alberto Dassatti

giotto-ph: A Python Library for High-Performance Computation of Persistent Homology of Vietoris-Rips Filtrations

18 pages, 7 figures

cs.CG cs.MS

http://creativecommons.org/licenses/by/4.0/

We introduce giotto-ph, a high-performance, open-source software package for the computation of Vietoris-Rips barcodes. giotto-ph is based on Morozov and Nigmetov's lockfree (multicore) implementation of Ulrich Bauer's Ripser package. It also contains a re-working of the GUDHI library's implementation of Boissonnat and Pritam's Edge Collapser, which can be used as a pre-processing step to dramatically reduce overall run-times in certain scenarios. Our contribution is twofold: on the one hand, we integrate existing state-of-the-art ideas coherently in a single library and provide Python bindings to the C++ code. On the other hand, we increase parallelization opportunities and improve overall performance by adopting more efficient data structures. Our persistent homology backend establishes a new state of the art, surpassing even GPU-accelerated implementations such as Ripser++ when using as few as 5-10 CPU cores. Furthermore, our implementation of Edge Collapser has fewer software dependencies and improved run-times relative to GUDHI's original implementation.

[{'version': 'v1', 'created': 'Mon, 12 Jul 2021 13:30:45 GMT'} {'version': 'v2', 'created': 'Mon, 2 Aug 2021 19:04:35 GMT'}]

2021-08-04

[array(['Pérez', 'Julián Burella', ''], dtype=object) array(['Hauke', 'Sydney', ''], dtype=object) array(['Lupo', 'Umberto', ''], dtype=object) array(['Caorsi', 'Matteo', ''], dtype=object) array(['Dassatti', 'Alberto', ''], dtype=object)]

1703.10290

Congliang Huang

Danchen Luo, Congliang Huang, Zun Huang

Decreased Thermal Conductivity of Polyethylene Chain Influenced by Short Chain Branching

cond-mat.mes-hall

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

In this paper, we have studied the effect of short branches on the thermal conductivity of a polyethylene (PE) chain. With a reverse non-equilibrium molecular dynamics method applied, thermal conductivities of the pristine PE chain and the PE-ethyl chain are simulated and compared. It shows that the branch has a positive effect to decrease the thermal conductivity of a PE chain. The thermal conductivity of the PE-ethyl chain decreases with the number density increase of the ethyl branches, until the density becomes larger than about 8 ethyl per 200 segments, where the thermal conductivity saturates to be only about 40% that of a pristine PE chain. Because of different weights, different types of branching chains will cause a different decrease of thermal conductivities, and a heavy branch will leads to a lower thermal conductivity than a light one. This study is expected to provide some fundamental guidance to obtain a polymer with a quite low thermal conductivity.

[{'version': 'v1', 'created': 'Thu, 30 Mar 2017 02:38:39 GMT'}]

2017-03-31

[array(['Luo', 'Danchen', ''], dtype=object) array(['Huang', 'Congliang', ''], dtype=object) array(['Huang', 'Zun', ''], dtype=object)]

1601.00064

Bruno Marcos

D Chiron (JAD), B Marcos (JAD)

Classical particle scattering for power-law two-body potentials

23 pages, 17 figures

cond-mat.stat-mech astro-ph.HE

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

We present a rigorous study of the classical scattering for anytwo-body inter-particle potential of the form $v(r)=g/r^\gamma$, with$\gamma\textgreater{}0$, for repulsive ($g\textgreater{}0$) and attractive ($g\textless{}0$)interactions. We give a derivation of the complete power series of thedeflection angle in terms of the impact factor for the weak scatteringregime (large impact factors) as well as the asymptotic expressionsfor the hard scattering regime (small impact factors). We see a verydifferent qualitative and quantitative behavior depending whether theinteraction is repulsive or attractive. In the latter case, thefamilies of trajectories depend also strongly on the value of$\gamma$. We also study carefully the modifications of the resultswhen a regularization is introduced in the potential at small scales.We check and illustrate all the results with the exact integration ofthe equations of motion.

[{'version': 'v1', 'created': 'Fri, 1 Jan 2016 09:26:55 GMT'}]

2016-01-05

[array(['Chiron', 'D', '', 'JAD'], dtype=object) array(['Marcos', 'B', '', 'JAD'], dtype=object)]

1903.04868

Jinsheng Chen

Jinsheng Chen, Giuseppe Greco, Alessandra Palmigiano, Apostolos Tzimoulis

Non normal logics: semantic analysis and proof theory

10.1007/978-3-662-59533-6_7

math.LO

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

We introduce proper display calculi for basic monotonic modal logic,the conditional logic CK and a number of their axiomatic extensions. These calculi are sound, complete, conservative and enjoy cut elimination and subformula property. Our proposal applies the multi-type methodology in the design of display calculi, starting from a semantic analysis based on the translation from monotonic modal logic to normal bi-modal logic.

[{'version': 'v1', 'created': 'Tue, 12 Mar 2019 12:28:48 GMT'}]

2019-10-22

[array(['Chen', 'Jinsheng', ''], dtype=object) array(['Greco', 'Giuseppe', ''], dtype=object) array(['Palmigiano', 'Alessandra', ''], dtype=object) array(['Tzimoulis', 'Apostolos', ''], dtype=object)]

1611.08939

Ben T. McAllister

Ben T. McAllister, Yifan Shen, Graeme R. Flower, Stephen R. Parker, and Michael E. Tobar

Higher Order Reentrant Post Modes in Cylindrical Cavities

8 pages, 11 figures. V2: As published in Journal of Applied Physics. V3: Typographical corrections. V4: New Appendix added

10.1063/1.4991751

physics.ins-det

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

Reentrant cavities are microwave resonant devices employed in a number of different areas of physics. They are appealing due to their simple frequency tuning mechanism, which offers large tuning ranges. Reentrant cavities are, in essence, 3D lumped LC circuits consisting of a conducting central post embedded in a resonant cavity. The lowest order reentrant mode (which transforms from the $TM_{010}$ mode) has been extensively studied in past publications. In this work we show the existence of higher order reentrant post modes (which transform from the $TM_{01n}$ mode family). We characterize these new modes in terms of their frequency tuning, filling factors and quality factors, as well as discuss some possible applications of these modes in fundamental physics tests. The appendix contains a comment on a paper related to this work.

[{'version': 'v1', 'created': 'Mon, 28 Nov 2016 00:04:00 GMT'} {'version': 'v2', 'created': 'Thu, 12 Oct 2017 14:30:36 GMT'} {'version': 'v3', 'created': 'Mon, 23 Oct 2017 12:20:47 GMT'} {'version': 'v4', 'created': 'Mon, 3 Dec 2018 04:41:44 GMT'}]

2018-12-04

[array(['McAllister', 'Ben T.', ''], dtype=object) array(['Shen', 'Yifan', ''], dtype=object) array(['Flower', 'Graeme R.', ''], dtype=object) array(['Parker', 'Stephen R.', ''], dtype=object) array(['Tobar', 'Michael E.', ''], dtype=object)]

1004.1645

Laura Man\v{c}inska

Andrew M. Childs, Debbie Leung, Laura Man\v{c}inska, Maris Ozols

Characterization of universal two-qubit Hamiltonians

Added Appendix D, showing how our results easily imply universality of almost any 2-qubit unitary

Quantum Information and Computation 11, 19-39 (2011)

10.26421/QIC11.1-2

quant-ph

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

Suppose we can apply a given 2-qubit Hamiltonian H to any (ordered) pair of qubits. We say H is n-universal if it can be used to approximate any unitary operation on n qubits. While it is well known that almost any 2-qubit Hamiltonian is 2-universal (Deutsch, Barenco, Ekert 1995; Lloyd 1995), an explicit characterization of the set of non-universal 2-qubit Hamiltonians has been elusive. Our main result is a complete characterization of 2-non-universal 2-qubit Hamiltonians. In particular, there are three ways that a 2-qubit Hamiltonian H can fail to be universal: (1) H shares an eigenvector with the gate that swaps two qubits, (2) H acts on the two qubits independently (in any of a certain family of bases), or (3) H has zero trace. A 2-non-universal 2-qubit Hamiltonian can still be n-universal for some n >= 3. We give some partial results on 3-universality. Finally, we also show how our characterization of 2-universal Hamiltonians implies the well-known result that almost any 2-qubit unitary is universal.

[{'version': 'v1', 'created': 'Fri, 9 Apr 2010 20:19:35 GMT'} {'version': 'v2', 'created': 'Wed, 10 Dec 2014 10:35:10 GMT'}]

2018-12-20

[array(['Childs', 'Andrew M.', ''], dtype=object) array(['Leung', 'Debbie', ''], dtype=object) array(['Mančinska', 'Laura', ''], dtype=object) array(['Ozols', 'Maris', ''], dtype=object)]

0710.2464

Alessandro Maselli Dr.

A. Maselli, P. Giommi, M. Perri, R. Nesci, A. Tramacere, F. Massaro, M. Capalbi

The 26 year-long X-ray light curve and the X-ray spectrum of the BL Lac Object 1E 1207.9+3945 in its brightest state

7 pages, 6 figures, accepted for publication in A&A

10.1051/0004-6361:20078401

astro-ph

We studied the temporal and spectral evolution of the synchrotron emission from the high energy peaked BL Lac object 1E 1207.9+3945. Two recent observations have been performed by the XMM-Newton and Swift satellites; we carried out X-ray spectral analysis for both of them, and photometry in optical-ultraviolet filters for the Swift one. Combining the results thus obtained with archival data we built the long-term X-ray light curve, spanning a time interval of 26 years, and the Spectral Energy Distribution (SED) of this source. The light curve shows a large flux increasing, about a factor of six, in a time interval of a few years. After reaching its maximum in coincidence with the XMM-Newton pointing in December 2000 the flux decreased in later years, as revealed by Swift. The very good statistics available in the 0.5-10 keV XMM-Newton X-ray spectrum points out a highly significant deviation from a single power law. A log-parabolic model with a best fit curvature parameter of 0.25 and a peak energy at ~1 keV describes well the spectral shape of the synchrotron emission. The simultaneous fit of Swift UVOT and XRT data provides a milder curvature (b~0.1) and a peak at higher energies (~15 keV), suggesting a different state of source activity. In both cases UVOT data support the scenario of a single synchrotron emission component extending from the optical/UV to the X-ray band. New X-ray observations are important to monitor the temporal and spectral evolution of the source; new generation gamma-ray telescopes like AGILE and GLAST could for the first time detect its inverse Compton emission.

[{'version': 'v1', 'created': 'Fri, 12 Oct 2007 14:04:04 GMT'}]

2009-11-13

[array(['Maselli', 'A.', ''], dtype=object) array(['Giommi', 'P.', ''], dtype=object) array(['Perri', 'M.', ''], dtype=object) array(['Nesci', 'R.', ''], dtype=object) array(['Tramacere', 'A.', ''], dtype=object) array(['Massaro', 'F.', ''], dtype=object) array(['Capalbi', 'M.', ''], dtype=object)]

1906.02546

Alessio Troiani

Valentina Apollonio, Roberto D'Autilia, Benedetto Scoppola, Elisabetta Scoppola, Alessio Troiani

Criticality of measures on 2-d Ising configurations: from square to hexagonal graphs

10.1007/s10955-019-02403-3

math-ph math.MP math.PR

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

On the space of Ising configurations on the 2-d square lattice, we consider a family of non Gibbsian measures introduced by using a pair Hamiltonian, depending on an additional inertial parameter $q$. These measures are related to the usual Gibbs measure on $\Z^2$ and turn out to be the marginal of the Gibbs measure of a suitable Ising model on the hexagonal lattice. The inertial parameter $q$ tunes the geometry of the system. The critical behaviour and the decay of correlation functions of these measures are studied thanks to relation with the Random Cluster model.

[{'version': 'v1', 'created': 'Thu, 6 Jun 2019 12:25:12 GMT'}]

2020-01-08

[array(['Apollonio', 'Valentina', ''], dtype=object) array(["D'Autilia", 'Roberto', ''], dtype=object) array(['Scoppola', 'Benedetto', ''], dtype=object) array(['Scoppola', 'Elisabetta', ''], dtype=object) array(['Troiani', 'Alessio', ''], dtype=object)]

1302.1958

Bojan Magajna

Bojan Magajna

Variance of operators and derivations

31 pages, to appear in JMAA. The paper has been reorganized and the proofs of a few results corrected. The statement of the former Theorem 5.8 (now Corollary 5.4) has been changed

math.FA math.OA

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

The variance of a bounded linear operator $a$ on a Hilbert space $H$ at a unit vector $h$ is defined by $D_h(a)=\|ah\|^2-|<ah,h>|^2$. We show that two operators $a$ and $b$ have the same variance at all vectors $h\in H$ if and only if there exist scalars $\sigma,\lambda$ with $|\sigma|=1$ such that $b=\sigma a+\lambda1$ or $a$ is normal and $b=\sigma a^*+\lambda1$. Further, if $a$ is normal, then the inequality $D_h(b)\leq\kappa D_h(a)$ holds for some constant $\kappa$ and all unit vectors $h$ if and only if $b=f(a)$ for a Lipschitz function $f$ on the spectrum of $a$. Variants of these results for C$^*$-algebras are also proved. We also study the related, but more restrictive inequalities $\|bx-xb\|\leq \|ax-xa\|$ supposed to hold for all $x\in B(H)$ or for all $x\in B(H^n)$ and all positive integers $n$. We consider the connection between such inequalities and the range inclusion $d_b(B(H))\subseteq d_a(B(H))$, where $d_a$ and $d_b$ are the derivations on $B(H)$ induced by $a$ and $b$. If $a$ is subnormal, we study these conditions in particular in the case when $b$ is of the form $b=f(a)$ for a function $f$.

[{'version': 'v1', 'created': 'Fri, 8 Feb 2013 07:30:47 GMT'} {'version': 'v2', 'created': 'Thu, 6 Aug 2015 09:17:20 GMT'}]

2015-08-07

[array(['Magajna', 'Bojan', ''], dtype=object)]

1902.05826

Nathan Kallus

Nathan Kallus and Angela Zhou

The Fairness of Risk Scores Beyond Classification: Bipartite Ranking and the xAUC Metric

cs.LG stat.ML

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

Where machine-learned predictive risk scores inform high-stakes decisions, such as bail and sentencing in criminal justice, fairness has been a serious concern. Recent work has characterized the disparate impact that such risk scores can have when used for a binary classification task. This may not account, however, for the more diverse downstream uses of risk scores and their non-binary nature. To better account for this, in this paper, we investigate the fairness of predictive risk scores from the point of view of a bipartite ranking task, where one seeks to rank positive examples higher than negative ones. We introduce the xAUC disparity as a metric to assess the disparate impact of risk scores and define it as the difference in the probabilities of ranking a random positive example from one protected group above a negative one from another group and vice versa. We provide a decomposition of bipartite ranking loss into components that involve the discrepancy and components that involve pure predictive ability within each group. We use xAUC analysis to audit predictive risk scores for recidivism prediction, income prediction, and cardiac arrest prediction, where it describes disparities that are not evident from simply comparing within-group predictive performance.

[{'version': 'v1', 'created': 'Fri, 15 Feb 2019 14:48:25 GMT'} {'version': 'v2', 'created': 'Sat, 1 Jun 2019 20:06:32 GMT'}]

2019-06-04

[array(['Kallus', 'Nathan', ''], dtype=object) array(['Zhou', 'Angela', ''], dtype=object)]

1305.0534

Robert Kleinberg

Robert Kleinberg and Yang Yuan

On the Ratio of Revenue to Welfare in Single-Parameter Mechanism Design

15 pages

cs.GT

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

What fraction of the potential social surplus in an environment can be extracted by a revenue-maximizing monopolist? We investigate this problem in Bayesian single-parameter environments with independent private values. The precise answer to the question obviously depends on the particulars of the environment: the feasibility constraint and the distributions from which the bidders' private values are sampled. Rather than solving the problem in particular special cases, our work aims to provide universal lower bounds on the revenue-to-welfare ratio that hold under the most general hypotheses that allow for non-trivial such bounds. Our results can be summarized as follows. For general feasibility constraints, the revenue-to-welfare ratio is at least a constant times the inverse-square-root of the number of agents, and this is tight up to constant factors. For downward-closed feasibility constraints, the revenue-to-welfare ratio is bounded below by a constant. Both results require the bidders' distributions to satisfy hypotheses somewhat stronger than regularity; we show that the latter result cannot avoid this requirement.

[{'version': 'v1', 'created': 'Thu, 2 May 2013 18:54:15 GMT'}]

2013-05-03

[array(['Kleinberg', 'Robert', ''], dtype=object) array(['Yuan', 'Yang', ''], dtype=object)]

2102.06326

Steve Dai

Steve Dai, Alicia Klinefelter, Haoxing Ren, Rangharajan Venkatesan, Ben Keller, Nathaniel Pinckney, Brucek Khailany

Verifying High-Level Latency-Insensitive Designs with Formal Model Checking

cs.LO cs.AR cs.FL

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

Latency-insensitive design mitigates increasing interconnect delay and enables productive component reuse in complex digital systems. This design style has been adopted in high-level design flows because untimed functional blocks connected through latency-insensitive interfaces provide a natural communication abstraction. However, latency-insensitive design with high-level languages also introduces a unique set of verification challenges that jeopardize functional correctness. In particular, bugs due to invalid consumption of inputs and deadlocks can be difficult to detect and debug with dynamic simulation methods. To tackle these two classes of bugs, we propose formal model checking methods to guarantee that a high-level latency-insensitive design is unaffected by invalid input data and is free of deadlock. We develop a well-structured verification wrapper for each property to automatically construct the corresponding formal model for checking. Our experiments demonstrate that the formal checks are effective in realistic bug scenarios from high-level designs.

[{'version': 'v1', 'created': 'Fri, 12 Feb 2021 01:56:23 GMT'}]

2021-02-19

[array(['Dai', 'Steve', ''], dtype=object) array(['Klinefelter', 'Alicia', ''], dtype=object) array(['Ren', 'Haoxing', ''], dtype=object) array(['Venkatesan', 'Rangharajan', ''], dtype=object) array(['Keller', 'Ben', ''], dtype=object) array(['Pinckney', 'Nathaniel', ''], dtype=object) array(['Khailany', 'Brucek', ''], dtype=object)]

2101.00429

Xiaotian Wang

Feng Zhou, Ying Liu, Jianhua Wang, Tie Yang, Hong Chen, Xiaotian Wang, and Zhenxiang Cheng

Intersecting topological nodal ring and nodal wall states in superhard superconductor FeB4

6 page, 8 figures

Phys. Rev. Materials 5, 074201 (2021)

10.1103/PhysRevMaterials.5.074201

cond-mat.mtrl-sci

http://creativecommons.org/licenses/by/4.0/

Novel materials with both topological nontrivial states and superconductivity have attracted considerable attention in recent years. Single-crystal FeB4 was recently synthesized and demonstrated to exhibit superconductivity at temperatures lower than 2.9 K, and its nanoindentation hardness was measured to be 65 GPa. In this study, based on first-principles calculation and the low-energy kp effective Hamiltonian, we found that this Pnnm-type superhard FeB4 superconductor hosts topological behaviors with intersecting nodal rings (INRs) in the k_x=0 and k_z=0 planes and nodal wall states in the k_y= {\pi} and k_z= {\pi} planes. The observed surface drum-head-like (D-H-L) states on the [100] and [001] surfaces confirmed the presence of INR states in this system. According to our investigation results, FeB4, with its superconductivity, superior mechanical behaviors, one-dimensional (1D) and two-dimensional topological elements, and D-H-L surface states, is an existing single-phase target material that can be used to realize the topological superconducting state in the near future.

[{'version': 'v1', 'created': 'Sat, 2 Jan 2021 11:30:10 GMT'}]

2021-08-04

[array(['Zhou', 'Feng', ''], dtype=object) array(['Liu', 'Ying', ''], dtype=object) array(['Wang', 'Jianhua', ''], dtype=object) array(['Yang', 'Tie', ''], dtype=object) array(['Chen', 'Hong', ''], dtype=object) array(['Wang', 'Xiaotian', ''], dtype=object) array(['Cheng', 'Zhenxiang', ''], dtype=object)]

2306.05963

Peter Hase

Zhuofan Ying, Peter Hase, Mohit Bansal

Adaptive Contextual Perception: How to Generalize to New Backgrounds and Ambiguous Objects

21 pages, 12 figures. Our code is available at https://github.com/zfying/AdaptiveContext

cs.CV cs.AI cs.LG

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

Biological vision systems make adaptive use of context to recognize objects in new settings with novel contexts as well as occluded or blurry objects in familiar settings. In this paper, we investigate how vision models adaptively use context for out-of-distribution (OOD) generalization and leverage our analysis results to improve model OOD generalization. First, we formulate two distinct OOD settings where the contexts are either irrelevant (Background-Invariance) or beneficial (Object-Disambiguation), reflecting the diverse contextual challenges faced in biological vision. We then analyze model performance in these two different OOD settings and demonstrate that models that excel in one setting tend to struggle in the other. Notably, prior works on learning causal features improve on one setting but hurt in the other. This underscores the importance of generalizing across both OOD settings, as this ability is crucial for both human cognition and robust AI systems. Next, to better understand the model properties contributing to OOD generalization, we use representational geometry analysis and our own probing methods to examine a population of models, and we discover that those with more factorized representations and appropriate feature weighting are more successful in handling Background-Invariance and Object-Disambiguation tests. We further validate these findings through causal intervention on representation factorization and feature weighting to demonstrate their causal effect on performance. Lastly, we propose new augmentation methods to enhance model generalization. These methods outperform strong baselines, yielding improvements in both in-distribution and OOD tests. In conclusion, to replicate the generalization abilities of biological vision, computer vision models must have factorized object vs. background representations and appropriately weight both kinds of features.

[{'version': 'v1', 'created': 'Fri, 9 Jun 2023 15:29:54 GMT'}]

2023-06-12

[array(['Ying', 'Zhuofan', ''], dtype=object) array(['Hase', 'Peter', ''], dtype=object) array(['Bansal', 'Mohit', ''], dtype=object)]

2303.16822

Ting Tao

Ting Tao, Ruyu Liu, Lianghai Xiao, Shaohua Pan

An inexact LPA for DC composite optimization and application to matrix completions with outliers

math.OC stat.ML

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

This paper is concerned with a class of DC composite optimization problems which, as an extension of convex composite optimization problems and DC programs with nonsmooth components, often arises in robust factorization models of low-rank matrix recovery. For this class of nonconvex and nonsmooth problems, we propose an inexact linearized proximal algorithm (iLPA) by computing in each step an inexact minimizer of a strongly convex majorization constructed with a partial linearization of their objective functions, and establish the global convergence of the generated iterate sequence under the Kurdyka-\L\"ojasiewicz (KL) property of a potential function. In particular, by leveraging the composite structure, we provide a verifiable condition for the potential function to have the KL property of exponent $1/2$ at the limit point, so for the iterate sequence to have a local R-linear convergence rate, and clarify its relationship with the regularity used in the convergence analysis of algorithms for convex composite optimization. Finally, our iLPA is applied to a robust factorization model for matrix completions with outliers, and numerical comparison with the Polyak subgradient method confirms its superiority in computing time and quality of solutions.

[{'version': 'v1', 'created': 'Wed, 29 Mar 2023 16:15:34 GMT'} {'version': 'v2', 'created': 'Wed, 17 May 2023 12:45:43 GMT'}]

2023-05-18

[array(['Tao', 'Ting', ''], dtype=object) array(['Liu', 'Ruyu', ''], dtype=object) array(['Xiao', 'Lianghai', ''], dtype=object) array(['Pan', 'Shaohua', ''], dtype=object)]

1407.3792

Roman Kogler

M. Baak, J. Cuth, J. Haller, A. Hoecker, R. Kogler, K. Moenig, M. Schott, J. Stelzer

The global electroweak fit at NNLO and prospects for the LHC and ILC

26 pages, 9 figures

10.1140/epjc/s10052-014-3046-5

DESY-14-124

hep-ph hep-ex

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

For a long time, global fits of the electroweak sector of the Standard Model (SM) have been used to exploit measurements of electroweak precision observables at lepton colliders (LEP, SLC), together with measurements at hadron colliders (Tevatron, LHC), and accurate theoretical predictions at multi-loop level, to constrain free parameters of the SM, such as the Higgs and top masses. Today, all fundamental SM parameters entering these fits are experimentally determined, including information on the Higgs couplings, and the global fits are used as powerful tools to assess the validity of the theory and to constrain scenarios for new physics. Future measurements at the Large Hadron Collider (LHC) and the International Linear Collider (ILC) promise to improve the experimental precision of key observables used in the fits. This paper presents updated electroweak fit results using newest NNLO theoretical predictions, and prospects for the LHC and ILC. The impact of experimental and theoretical uncertainties is analysed in detail. We compare constraints from the electroweak fit on the Higgs couplings with direct LHC measurements, and examine present and future prospects of these constraints using a model with modified couplings of the Higgs boson to fermions and bosons.

[{'version': 'v1', 'created': 'Mon, 14 Jul 2014 20:00:04 GMT'}]

2015-06-22

[array(['Baak', 'M.', ''], dtype=object) array(['Cuth', 'J.', ''], dtype=object) array(['Haller', 'J.', ''], dtype=object) array(['Hoecker', 'A.', ''], dtype=object) array(['Kogler', 'R.', ''], dtype=object) array(['Moenig', 'K.', ''], dtype=object) array(['Schott', 'M.', ''], dtype=object) array(['Stelzer', 'J.', ''], dtype=object)]

hep-th/9301010

Alok Kumar

Abbas Ali and Alok Kumar

A New $N = 4$ Superconformal Algebra

10 pages, Latex, IP/BBSR/92-90

Mod.Phys.Lett. A8 (1993) 1527-1532

10.1142/S0217732393001252

hep-th

It is shown that the previously known $N=3$ and $N=4$ superconformal algebras can be contracted consistently by singular scaling of some of the generators. For the later case, by a contraction which depends on the central term, we obtain a new $N=4$ superconformal algebra which contains an $SU(2)\times {U(1)}^4$ Kac-Moody subalgebra and has nonzero central extension.

[{'version': 'v1', 'created': 'Mon, 4 Jan 1993 13:06:16 GMT'}]

2015-06-26

[array(['Ali', 'Abbas', ''], dtype=object) array(['Kumar', 'Alok', ''], dtype=object)]

2110.15002

Ivan Girardi

Ivan Girardi, Panagiotis Vagenas, Dario Arcos-D\'iaz, Lydia Bessa\"i, Alexander B\"usser, Ludovico Furlan, Raffaello Furlan, Mauro Gatti, Andrea Giovannini, Ellen Hoeven, Chiara Marchiori

On the explainability of hospitalization prediction on a large COVID-19 patient dataset

10 pages, 5 figures, accepted to AMIA 2021

cs.LG

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

We develop various AI models to predict hospitalization on a large (over 110$k$) cohort of COVID-19 positive-tested US patients, sourced from March 2020 to February 2021. Models range from Random Forest to Neural Network (NN) and Time Convolutional NN, where combination of the data modalities (tabular and time dependent) are performed at different stages (early vs. model fusion). Despite high data unbalance, the models reach average precision 0.96-0.98 (0.75-0.85), recall 0.96-0.98 (0.74-0.85), and $F_1$-score 0.97-0.98 (0.79-0.83) on the non-hospitalized (or hospitalized) class. Performances do not significantly drop even when selected lists of features are removed to study model adaptability to different scenarios. However, a systematic study of the SHAP feature importance values for the developed models in the different scenarios shows a large variability across models and use cases. This calls for even more complete studies on several explainability methods before their adoption in high-stakes scenarios.

[{'version': 'v1', 'created': 'Thu, 28 Oct 2021 10:23:38 GMT'}]

2021-10-29

[array(['Girardi', 'Ivan', ''], dtype=object) array(['Vagenas', 'Panagiotis', ''], dtype=object) array(['Arcos-Díaz', 'Dario', ''], dtype=object) array(['Bessaï', 'Lydia', ''], dtype=object) array(['Büsser', 'Alexander', ''], dtype=object) array(['Furlan', 'Ludovico', ''], dtype=object) array(['Furlan', 'Raffaello', ''], dtype=object) array(['Gatti', 'Mauro', ''], dtype=object) array(['Giovannini', 'Andrea', ''], dtype=object) array(['Hoeven', 'Ellen', ''], dtype=object) array(['Marchiori', 'Chiara', ''], dtype=object)]

1906.10857

Neri Merhav

Neri Merhav

Guessing Individual Sequences: Generating Randomized Guesses Using Finite-State Machines

23 pages, 1 figure, submitted for publication

cs.IT math.IT

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

Motivated by earlier results on universal randomized guessing, we consider an individual-sequence approach to the guessing problem: in this setting, the goal is to guess a secret, individual (deterministic) vector $x^n=(x_1,\ldots,x_n)$, by using a finite-state machine that sequentially generates randomized guesses from a stream of purely random bits. We define the finite-state guessing exponent as the asymptotic normalized logarithm of the minimum achievable moment of the number of randomized guesses, generated by any finite-state machine, until $x^n$ is guessed successfully. We show that the finite-state guessing exponent of any sequence is intimately related to its finite-state compressibility (due to Lempel and Ziv), and it is asymptotically achieved by the decoder of (a certain modified version of) the 1978 Lempel-Ziv data compression algorithm (a.k.a. the LZ78 algorithm), fed by purely random bits. The results are also extended to the case where the guessing machine has access to a side information sequence, $y^n=(y_1,\ldots,y_n)$, which is also an individual sequence.

[{'version': 'v1', 'created': 'Wed, 26 Jun 2019 06:10:57 GMT'}]

2019-06-27

[array(['Merhav', 'Neri', ''], dtype=object)]

nlin/0210063

Douglas N. Armstead

D. N. Armstead, B. R. Hunt, Edward Ott

Long Time Algebraic Relaxation in Chaotic Billiards

4 pages, 5 figures, submitted to PRL

Phys. Rev. Lett. 89, 284101 (2002)

10.1103/PhysRevLett.89.284101

nlin.CG

The long time algebraic relaxation process in spatially periodic billiards with infinite horizon is shown to display a self-similar time asymptotic form. This form is identical for a class of such billiards, but can be different in an important special case.

[{'version': 'v1', 'created': 'Mon, 28 Oct 2002 22:30:52 GMT'}]

2009-11-07

[array(['Armstead', 'D. N.', ''], dtype=object) array(['Hunt', 'B. R.', ''], dtype=object) array(['Ott', 'Edward', ''], dtype=object)]

2111.11077

Christian Ginski

C. Ginski, R. Gratton, A. Bohn, C. Dominik, S. Jorquera, G. Chauvin, J. Milli, M. Rodriguez, M. Benisty, R. Launhardt, A. Mueller, G. Cugno, R.G. van Holstein, A. Boccaletti, G. A. Muro-Arena, S. Desidera, M. Keppler, A. Zurlo, E. Sissa, T. Henning, M. Janson, M. Langlois, M. Bonnefoy, F. Cantalloube, V. D'Orazi, M. Feldt, J. Hagelberg, D. Segransan, A-M. Lagrange, C. Lazzoni, M. Meyer, C. Romero, T.O.B. Schmidt, A. Vigan, C. Petit, R. Roelfsema, J. Pragt, L. Weber

An extended scattered light disk around AT Pyx -- Possible planet formation in a cometary globule

11 pages, 9 figures, accepted for publication in A&A

A&A 662, A74 (2022)

10.1051/0004-6361/202142269

astro-ph.EP astro-ph.SR

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

To understand how the multitude of planetary systems that have been discovered come to be, we need to study systems at different evolutionary stages, with different central stars but also in different environments. The most challenging environment for planet formation may be the harsh UV radiation field of nearby massive stars which quickly erodes disks by external photo-evaporation. We have observed the AT Pyx system, located in the head of a cometary globule in the Gum Nebula, to search for signs of ongoing planet formation. We used the extreme adaptive optics imager VLT/SPHERE to observe AT Pyx in polarized light as well as total intensity in the J, H and K-band. Additionally we employed VLT/NACO to observe the system in the L-band. We resolve the disk around AT Pyx in scattered light across multiple wavelengths. We find an extended (>126 au) disk, with an intermediate inclination between 35 deg and 42 deg. The disk shows complex sub-structure and we identify 2 and possibly 3 spiral-like features. Depending on the precise geometry of the disk (which we can not unambiguously infer from our data) the disk may be eccentric with an eccentricity of ~0.16 or partially self-shadowed. The spiral features and possible eccentricity are both consistent with signatures of an embedded gas giant planet equal in mass to Jupiter. Our own observations can rule out brown dwarf companions embedded in the resolved disk, but are not sensitive enough to detect gas giants. AT Pyx is the first disk in a cometray globule in the Gum Nebula which is spatially resolved. By comparison with disks in the Orion Nebula Cluster we note that the extension of the disk may be exceptional for this environment if the external UV radiation field is comparable to other cometary globules in the region. The signposts of ongoing planet formation are intriguing and need to be followed up with higher sensitivity.

[{'version': 'v1', 'created': 'Mon, 22 Nov 2021 09:40:41 GMT'}]

2022-06-22

[array(['Ginski', 'C.', ''], dtype=object) array(['Gratton', 'R.', ''], dtype=object) array(['Bohn', 'A.', ''], dtype=object) array(['Dominik', 'C.', ''], dtype=object) array(['Jorquera', 'S.', ''], dtype=object) array(['Chauvin', 'G.', ''], dtype=object) array(['Milli', 'J.', ''], dtype=object) array(['Rodriguez', 'M.', ''], dtype=object) array(['Benisty', 'M.', ''], dtype=object) array(['Launhardt', 'R.', ''], dtype=object) array(['Mueller', 'A.', ''], dtype=object) array(['Cugno', 'G.', ''], dtype=object) array(['van Holstein', 'R. G.', ''], dtype=object) array(['Boccaletti', 'A.', ''], dtype=object) array(['Muro-Arena', 'G. A.', ''], dtype=object) array(['Desidera', 'S.', ''], dtype=object) array(['Keppler', 'M.', ''], dtype=object) array(['Zurlo', 'A.', ''], dtype=object) array(['Sissa', 'E.', ''], dtype=object) array(['Henning', 'T.', ''], dtype=object) array(['Janson', 'M.', ''], dtype=object) array(['Langlois', 'M.', ''], dtype=object) array(['Bonnefoy', 'M.', ''], dtype=object) array(['Cantalloube', 'F.', ''], dtype=object) array(["D'Orazi", 'V.', ''], dtype=object) array(['Feldt', 'M.', ''], dtype=object) array(['Hagelberg', 'J.', ''], dtype=object) array(['Segransan', 'D.', ''], dtype=object) array(['Lagrange', 'A-M.', ''], dtype=object) array(['Lazzoni', 'C.', ''], dtype=object) array(['Meyer', 'M.', ''], dtype=object) array(['Romero', 'C.', ''], dtype=object) array(['Schmidt', 'T. O. B.', ''], dtype=object) array(['Vigan', 'A.', ''], dtype=object) array(['Petit', 'C.', ''], dtype=object) array(['Roelfsema', 'R.', ''], dtype=object) array(['Pragt', 'J.', ''], dtype=object) array(['Weber', 'L.', ''], dtype=object)]

2306.03559

Ravindra Pawar

Ravindra Pawar, Tarkeshwar Singh, Adarsh Handa, Aloysius Godinho

Local Antimagic Coloring of Some Graphs

math.CO

http://creativecommons.org/licenses/by/4.0/

Given a graph $G =(V,E)$, a bijection $f: E \rightarrow \{1, 2, \dots,|E|\}$ is called a local antimagic labeling of $G$ if the vertex weight $w(u) = \sum_{uv \in E} f(uv)$ is distinct for all adjacent vertices. The vertex weights under the local antimagic labeling of $G$ induce a proper vertex coloring of a graph $G$. The \textit{local antimagic chromatic number} of $G$ denoted by $\chi_{la}(G)$ is the minimum number of weights taken over all such local antimagic labelings of $G$. In this paper, we investigate the local antimagic chromatic numbers of the union of some families of graphs, corona product of graphs, and necklace graph and we construct infinitely many graphs satisfying $\chi_{la}(G) = \chi(G)$.

[{'version': 'v1', 'created': 'Tue, 6 Jun 2023 10:20:59 GMT'}]

2023-06-07

[array(['Pawar', 'Ravindra', ''], dtype=object) array(['Singh', 'Tarkeshwar', ''], dtype=object) array(['Handa', 'Adarsh', ''], dtype=object) array(['Godinho', 'Aloysius', ''], dtype=object)]

2001.01047

Muhammad Haroon Shakeel

Muhammad Haroon Shakeel, Asim Karim

Adapting Deep Learning for Sentiment Classification of Code-Switched Informal Short Text

The 35th ACM/SIGAPP Symposium on Applied Computing (SAC) 2020

10.1145/3341105.3374091

cs.CL

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

Nowadays, an abundance of short text is being generated that uses nonstandard writing styles influenced by regional languages. Such informal and code-switched content are under-resourced in terms of labeled datasets and language models even for popular tasks like sentiment classification. In this work, we (1) present a labeled dataset called MultiSenti for sentiment classification of code-switched informal short text, (2) explore the feasibility of adapting resources from a resource-rich language for an informal one, and (3) propose a deep learning-based model for sentiment classification of code-switched informal short text. We aim to achieve this without any lexical normalization, language translation, or code-switching indication. The performance of the proposed models is compared with three existing multilingual sentiment classification models. The results show that the proposed model performs better in general and adapting character-based embeddings yield equivalent performance while being computationally more efficient than training word-based domain-specific embeddings.

[{'version': 'v1', 'created': 'Sat, 4 Jan 2020 06:31:15 GMT'}]

2020-04-07

[array(['Shakeel', 'Muhammad Haroon', ''], dtype=object) array(['Karim', 'Asim', ''], dtype=object)]

1010.3624

Christophe Bahadoran

Christophe Bahadoran

A quasi-potential for conservation laws with boundary conditions

71 pages

math-ph math.AP math.MP

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

We compute the quasi-potential and determine minimizing paths for an action functional related to scalar conservation laws on an interval with boundary conditions in the sense of Bardos et al. (1979). Taking as input an exclusion-like flux function, a strictly convex entropy, and boundary data, we obtain a generalization of the functional derived by Derrida, Lebowtiz and Speer (2003) for the stationary large deviations of the asymmetric exclusion process.

[{'version': 'v1', 'created': 'Mon, 18 Oct 2010 15:11:57 GMT'}]

2010-10-19

[array(['Bahadoran', 'Christophe', ''], dtype=object)]

2207.08837

Andris Dorozsmai Mr

Andris Dorozsmai, Silvia Toonen

Importance of stable mass transfer and stellar winds for the formation of gravitational wave sources

30 pages with 6 pages of appendices

astro-ph.SR astro-ph.HE gr-qc

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

The large number of gravitational wave (GW) detections have revealed the properties of the merging black hole binary population, but their formation is still heavily debated. Understanding the imprint of stellar physics on the observable GW population will shed light on how we can use the gravitational wave data, along with other observations, to constrain the poorly understood evolution of massive binaries. We perform a parameter study for the classical isolated binary formation channel in order to better understand how sensitive the properties of the coalescing binary black hole population are on uncertainties related of stable mass transfer phase and stellar winds. We use the population synthesis code SeBa to simulate the evolution of massive binaries on a large range of metallicities. We vary five assumptions: 1 and 2) the mass transfer efficiency and the angular momentum loss during the first mass transfer phase, 3) the mass transfer stability criteria for giant donors with radiative envelopes, 4) the effective temperature at which an evolved star develops a deep convective envelope, and 5) the stellar winds. Our varied parameters have a complex, interrelated effects on the population properties of GW sources. Most notably, the impact of the mass transfer stability criteria parameter depends on the assumed mass transfer efficiency. The uncertainties in the assumed angular momentum loss have significant effects on the relative rates of the two dominant channels. Because of the numerous uncertainties and lack of reliable models direct inference of massive binary physics from gravitational data is not recommended.

[{'version': 'v1', 'created': 'Mon, 18 Jul 2022 18:00:04 GMT'}]

2022-07-20

[array(['Dorozsmai', 'Andris', ''], dtype=object) array(['Toonen', 'Silvia', ''], dtype=object)]

1810.05992

Satoshi Hara

Satoshi Hara, Takanori Maehara

Convex Hull Approximation of Nearly Optimal Lasso Solutions

14pages

stat.ML cs.LG

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

In an ordinary feature selection procedure, a set of important features is obtained by solving an optimization problem such as the Lasso regression problem, and we expect that the obtained features explain the data well. In this study, instead of the single optimal solution, we consider finding a set of diverse yet nearly optimal solutions. To this end, we formulate the problem as finding a small number of solutions such that the convex hull of these solutions approximates the set of nearly optimal solutions. The proposed algorithm consists of two steps: First, we randomly sample the extreme points of the set of nearly optimal solutions. Then, we select a small number of points using a greedy algorithm. The experimental results indicate that the proposed algorithm can approximate the solution set well. The results also indicate that we can obtain Lasso solutions with a large diversity.

[{'version': 'v1', 'created': 'Sun, 14 Oct 2018 08:10:54 GMT'}]

2018-10-16

[array(['Hara', 'Satoshi', ''], dtype=object) array(['Maehara', 'Takanori', ''], dtype=object)]

2204.10232

Wei Tang

Wei Tang, Yanlin Wang, Hongyu Zhang, Shi Han, Ping Luo, Dongmei Zhang

LibDB: An Effective and Efficient Framework for Detecting Third-Party Libraries in Binaries

MSR 2022

10.1145/3524842.3528442

cs.CR cs.SE

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

Third-party libraries (TPLs) are reused frequently in software applications for reducing development cost. However, they could introduce security risks as well. Many TPL detection methods have been proposed to detect TPL reuse in Android bytecode or in source code. This paper focuses on detecting TPL reuse in binary code, which is a more challenging task. For a detection target in binary form, libraries may be compiled and linked to separate dynamic-link files or built into a fused binary that contains multiple libraries and project-specific code. This could result in fewer available code features and lower the effectiveness of feature engineering. In this paper, we propose a binary TPL reuse detection framework, LibDB, which can effectively and efficiently detect imported TPLs even in stripped and fused binaries. In addition to the basic and coarse-grained features (string literals and exported function names), LibDB utilizes function contents as a new type of feature. It embeds all functions in a binary file to low-dimensional representations with a trained neural network. It further adopts a function call graph-based comparison method to improve the accuracy of the detection. LibDB is able to support version identification of TPLs contained in the detection target, which is not considered by existing detection methods. To evaluate the performance of LibDB, we construct three datasets for binary-based TPL reuse detection. Our experimental results show that LibDB is more accurate and efficient than state-of-the-art tools on the binary TPL detection task and the version identification task. Our datasets and source code used in this work are anonymously available at https://github.com/DeepSoftwareAnalytics/LibDB.

[{'version': 'v1', 'created': 'Thu, 21 Apr 2022 16:10:03 GMT'}]

2022-04-22

[array(['Tang', 'Wei', ''], dtype=object) array(['Wang', 'Yanlin', ''], dtype=object) array(['Zhang', 'Hongyu', ''], dtype=object) array(['Han', 'Shi', ''], dtype=object) array(['Luo', 'Ping', ''], dtype=object) array(['Zhang', 'Dongmei', ''], dtype=object)]

1002.2618

Martin Bojowald

Martin Bojowald

Quantum gravity effects on space-time

24 pages, 4 figures, plenary talk at The Nineteenth Workshop on General Relativity and Gravitation in Japan (JGRG19) at Rikkyo University, Dec 2009

gr-qc

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

General relativity promotes space-time to a physical, dynamical object subject to equations of motion. Quantum gravity, accordingly, must provide a quantum framework for space-time, applicable on the smallest distance scales. Just like generic states in quantum mechanics, quantum space-time structures may be highly counter-intuitive. But if low-energy effects can be extracted, they shed considerable light on the implications to be expected for a dynamical quantum space-time. Loop quantum gravity has provided several such effects, but even in the symmetry-reduced setting of loop quantum cosmology no complete picture of effective space-time geometries describing especially the regime near the big bang has been obtained. The overall situation regarding space-time structures and cosmology is reviewed here, with an emphasis on the role of dynamical states, effective equations, and general covariance.

[{'version': 'v1', 'created': 'Fri, 12 Feb 2010 18:59:11 GMT'}]

2010-02-15

[array(['Bojowald', 'Martin', ''], dtype=object)]

1111.2554

Carlo Carminati

Carlo Carminati, Giulio Tiozzo

Tuning and plateaux for the entropy of $\alpha$-continued fractions

20 pages, 2 figures. This version has been considerably expanded, and contains a new result (Theorem 3) classifying local behaviour of the entropy. We have also added several statements and proofs in order to avoid external references. Last but not least, we added an appendix which explains how the techniques we use are derived from Douady-Hubbard tuning for quadratic polynomials

Nonlinearity 26 (2013), pp. 1049-1070

10.1088/0951-7715/26/4/1049

math.DS

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

The entropy $h(T_\alpha)$ of $\alpha$-continued fraction transformations is known to be locally monotone outside a closed, totally disconnected set $\EE$. We will exploit the explicit description of the fractal structure of $\EE$ to investigate the self-similarities displayed by the graph of the function $\alpha \mapsto h(T_\alpha)$. Finally, we completely characterize the plateaux occurring in this graph, and classify the local monotonic behaviour.

[{'version': 'v1', 'created': 'Thu, 10 Nov 2011 18:44:30 GMT'} {'version': 'v2', 'created': 'Thu, 31 May 2012 09:55:52 GMT'}]

2015-06-03

[array(['Carminati', 'Carlo', ''], dtype=object) array(['Tiozzo', 'Giulio', ''], dtype=object)]

math/0209298

Holger Brenner

Holger Brenner

The affine class group of a normal scheme

to appear in Communications in Algebra

Communications in Algebra 31, 6 (2003), 2849-2867

math.AC math.AG

We study the property of a normal scheme, that the complement of every hypersurface is an affine scheme. To this end we introduce the affine class group. It is a factor group of the divisor class group and measures the deviation from this property. We study the behaviour of the affine class group under faithfully flat extensions and under the formation of products, and we compute it for different classes of rings.

[{'version': 'v1', 'created': 'Mon, 23 Sep 2002 14:34:53 GMT'}]

2009-09-29

[array(['Brenner', 'Holger', ''], dtype=object)]

cond-mat/9604156

Clare Yu

Clare C. Yu

A Numerical Renormalization Group Study of a Kondo Hole in a One Dimensional Kondo Insulator

Revtex + postscript figures uuencoded

10.1103/PhysRevB.54.15917

cond-mat

We have studied a Kondo hole in a one-dimensional Kondo insulator at half-filling using a density matrix formulation of the numerical renormalization group. The Kondo hole introduces midgap states. The spin density introduced by the hole is localized in the vicinity of the hole. It resides primarily in the f-spins for small exchange coupling $J$ and in the conduction spins for large $J$. We present results on the spin gap, charge gap, and neutral gap. For small $J$, the spin gap is smaller than the charge gap, while for large $J$, the spin gap is larger than the charge gap. The presence of the Kondo hole reduces RKKY interactions as can be seen in the staggered susceptibility.

[{'version': 'v1', 'created': 'Wed, 24 Apr 1996 21:13:21 GMT'}]

2009-10-28

[array(['Yu', 'Clare C.', ''], dtype=object)]

2112.02918

Franziska Boenisch

Franziska Boenisch, Adam Dziedzic, Roei Schuster, Ali Shahin Shamsabadi, Ilia Shumailov, Nicolas Papernot

When the Curious Abandon Honesty: Federated Learning Is Not Private

cs.LG cs.CR cs.DC

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

In federated learning (FL), data does not leave personal devices when they are jointly training a machine learning model. Instead, these devices share gradients, parameters, or other model updates, with a central party (e.g., a company) coordinating the training. Because data never "leaves" personal devices, FL is often presented as privacy-preserving. Yet, recently it was shown that this protection is but a thin facade, as even a passive, honest-but-curious attacker observing gradients can reconstruct data of individual users contributing to the protocol. In this work, we show a novel data reconstruction attack which allows an active and dishonest central party to efficiently extract user data from the received gradients. While prior work on data reconstruction in FL relies on solving computationally expensive optimization problems or on making easily detectable modifications to the shared model's architecture or parameters, in our attack the central party makes inconspicuous changes to the shared model's weights before sending them out to the users. We call the modified weights of our attack trap weights. Our active attacker is able to recover user data perfectly, i.e., with zero error, even when this data stems from the same class. Recovery comes with near-zero costs: the attack requires no complex optimization objectives. Instead, our attacker exploits inherent data leakage from model gradients and simply amplifies this effect by maliciously altering the weights of the shared model through the trap weights. These specificities enable our attack to scale to fully-connected and convolutional deep neural networks trained with large mini-batches of data. For example, for the high-dimensional vision dataset ImageNet, we perfectly reconstruct more than 50% of the training data points from mini-batches as large as 100 data points.

[{'version': 'v1', 'created': 'Mon, 6 Dec 2021 10:37:03 GMT'} {'version': 'v2', 'created': 'Wed, 12 Apr 2023 21:27:15 GMT'}]

2023-04-14

[array(['Boenisch', 'Franziska', ''], dtype=object) array(['Dziedzic', 'Adam', ''], dtype=object) array(['Schuster', 'Roei', ''], dtype=object) array(['Shamsabadi', 'Ali Shahin', ''], dtype=object) array(['Shumailov', 'Ilia', ''], dtype=object) array(['Papernot', 'Nicolas', ''], dtype=object)]

1912.12435

Guozhen Shen

Guozhen Shen

A choice-free cardinal equality

12 pages

Notre Dame J. Formal Logic 62(3): 577-587 (August 2021)

10.1215/00294527-2021-0028

math.LO

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

For a cardinal $\mathfrak{a}$, let $\mathrm{fin}(\mathfrak{a})$ be the cardinality of the set of all finite subsets of a set which is of cardinality $\mathfrak{a}$. It is proved without the aid of the axiom of choice that for all infinite cardinals $\mathfrak{a}$ and all natural numbers $n$, \[ 2^{\mathrm{fin}(\mathfrak{a})^n}=2^{[\mathrm{fin}(\mathfrak{a})]^n}. \] On the other hand, it is proved that the following statement is consistent with $\mathsf{ZF}$: there exists an infinite cardinal $\mathfrak{a}$ such that \[ 2^{\mathrm{fin}(\mathfrak{a})}<2^{\mathrm{fin}(\mathfrak{a})^2}<2^{\mathrm{fin}(\mathfrak{a})^3}<\dots<2^{\mathrm{fin}(\mathrm{fin}(\mathfrak{a}))}. \]

[{'version': 'v1', 'created': 'Sat, 28 Dec 2019 10:26:19 GMT'}]

2021-11-02

[array(['Shen', 'Guozhen', ''], dtype=object)]

2111.10610

Gao Long

Long Gao, Chang Liu, Dooman Arefan, Ashok Panigrahy, Shandong Wu

Constrained Deep One-Class Feature Learning For Classifying Imbalanced Medical Images

Corrected inaccurate information in affiliation and acknowledgment

eess.IV cs.CV cs.LG

http://creativecommons.org/licenses/by/4.0/

Medical image data are usually imbalanced across different classes. One-class classification has attracted increasing attention to address the data imbalance problem by distinguishing the samples of the minority class from the majority class. Previous methods generally aim to either learn a new feature space to map training samples together or to fit training samples by autoencoder-like models. These methods mainly focus on capturing either compact or descriptive features, where the information of the samples of a given one class is not sufficiently utilized. In this paper, we propose a novel deep learning-based method to learn compact features by adding constraints on the bottleneck features, and to preserve descriptive features by training an autoencoder at the same time. Through jointly optimizing the constraining loss and the autoencoder's reconstruction loss, our method can learn more relevant features associated with the given class, making the majority and minority samples more distinguishable. Experimental results on three clinical datasets (including the MRI breast images, FFDM breast images and chest X-ray images) obtains state-of-art performance compared to previous methods.

[{'version': 'v1', 'created': 'Sat, 20 Nov 2021 15:25:24 GMT'} {'version': 'v2', 'created': 'Thu, 14 Apr 2022 08:17:46 GMT'}]

2022-04-15

[array(['Gao', 'Long', ''], dtype=object) array(['Liu', 'Chang', ''], dtype=object) array(['Arefan', 'Dooman', ''], dtype=object) array(['Panigrahy', 'Ashok', ''], dtype=object) array(['Wu', 'Shandong', ''], dtype=object)]

cond-mat/0311052

Lev Mourokh

Anatoly Yu. Smirnov and Lev G. Mourokh

Temperature dependence of electron transport through a quantum shuttle

Phys. Rev. B 69, 155310 (2004)

10.1103/PhysRevB.69.155310

cond-mat.mtrl-sci

We analyze electron transport through a quantum shuttle for the applied voltage below the instability threshold. We obtain current-voltage characteristics of this system and show that at low temperature they exhibit pronounced steps. The temperature dependence of the current is calculated in the range from 2K to 300K and it demonstrates a wide variety of behavior - from 1/T decreasing to an exponential growth - depending on how deep the shuttle is in quantum regime. The results obtained are compared to experimental data on electron transport through long molecules.

[{'version': 'v1', 'created': 'Mon, 3 Nov 2003 23:02:37 GMT'}]

2009-11-10

[array(['Smirnov', 'Anatoly Yu.', ''], dtype=object) array(['Mourokh', 'Lev G.', ''], dtype=object)]

cond-mat/0109477

R. J. Nicholas

M. Roberts, Y.C. Chung, S. Lyapin, N.J. Mason, R.J. Nicholas, P.C. Klipstein

Vertical transport and electroluminescence in InAs/GaSb/InAs structures: GaSb thickness and hydrostatic pressure studies

8 pages 12 figs

10.1103/PhysRevB.65.235326

cond-mat.mes-hall

We have measured the current-voltage (I-V) of type II InAs/GaSb/InAs double heterojunctions (DHETs) with 'GaAs like' interface bonding and GaSb thickness between 0-1200 \AA. A negative differential resistance (NDR) is observed for all DHETs with GaSb thickness $>$ 60 \AA below which a dramatic change in the shape of the I-V and a marked hysteresis is observed. The temperature dependence of the I-V is found to be very strong below this critical GaSb thickness. The I-V characteristics of selected DHETs are also presented under hydrostatic pressures up to 11 kbar. Finally, a mid infra-red electroluminescence is observed at 1 bar with a threshold at the NDR valley bias. The band profile calculations presented in the analysis are markedly different to those given in the literature, and arise due to the positive charge that it is argued will build up in the GaSb layer under bias. We conclude that the dominant conduction mechanism in DHETs is most likely to arise out of an inelastic electron-heavy-hole interaction similar to that observed in single heterojunctions (SHETs) with 'GaAs like' interface bonding, and not out of resonant electron-light-hole tunnelling as proposed by Yu et al. A Zener tunnelling mechanism is shown to contribute to the background current beyond NDR.

[{'version': 'v1', 'created': 'Wed, 26 Sep 2001 18:47:26 GMT'}]

2009-11-07

[array(['Roberts', 'M.', ''], dtype=object) array(['Chung', 'Y. C.', ''], dtype=object) array(['Lyapin', 'S.', ''], dtype=object) array(['Mason', 'N. J.', ''], dtype=object) array(['Nicholas', 'R. J.', ''], dtype=object) array(['Klipstein', 'P. C.', ''], dtype=object)]

math/0403468

Alexandru Tamasan

Alexandru Tamasan

On the scattering for the $\bar{\partial}$- equation and reconstruction of convection terms

13pages

math.AP math.CV

In this paper we reconstruct convection terms from boundary measurements.We reduce the Beals and Coifman inverse scattering scattering formalism from a first order system to a formalism for the $\bar{\partial}$ equation.

[{'version': 'v1', 'created': 'Fri, 26 Mar 2004 17:10:17 GMT'}]

2007-05-23

[array(['Tamasan', 'Alexandru', ''], dtype=object)]

0807.0143

Phuong Mai Dinh

P. M. Dinh, F. Fehrer, P.-G. Reinhard, and E. Suraud

Deposition dynamics of Na monomers and dimers on an Ar(001) substrate

8 figures, to be published in Surf. Sci. (2008)

Surf. Sci. 602 (2008) 2699

10.1016/j.susc.2008.06.024

cond-mat.mtrl-sci

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

We study deposition dynamics of Na and Na$_2$ on an Ar substrate, both species neutral as well as charged. The system is modeled by a hierarchical approach describing the Na valence electrons by time-dependent density-functional theory while Na core, Ar atoms and their dynamical polarizability are treated by molecular dynamics. We explore effects of Na charge and initial kinetic energy of the impinging Na system. We find that neutral Na is captured into a loosely bound adsorbate state for sufficiently low impact energy. The charged monomers are more efficiently captured and the cation Na$^+$ even penetrates the surface layer. For charged dimers, we come to different final configurations depending on the process, direct deposit of Na$_2^+$ as a whole, or sequential deposit. In any case, charge dramatically amplifies the excitation of the matrix, in particular at the side of the Ar dipoles. The presence of a charge also enhances the binding to the surface and favours accumulation of larger compounds.

[{'version': 'v1', 'created': 'Tue, 1 Jul 2008 13:06:34 GMT'}]

2009-11-13

[array(['Dinh', 'P. M.', ''], dtype=object) array(['Fehrer', 'F.', ''], dtype=object) array(['Reinhard', 'P. -G.', ''], dtype=object) array(['Suraud', 'E.', ''], dtype=object)]

2209.14610

Pan Lu

Pan Lu, Liang Qiu, Kai-Wei Chang, Ying Nian Wu, Song-Chun Zhu, Tanmay Rajpurohit, Peter Clark, Ashwin Kalyan

Dynamic Prompt Learning via Policy Gradient for Semi-structured Mathematical Reasoning

ICLR 2023. 26 pages and 18 figures. The data and code are available at https://promptpg.github.io

cs.LG cs.AI cs.CL cs.CV

http://creativecommons.org/licenses/by/4.0/

Mathematical reasoning, a core ability of human intelligence, presents unique challenges for machines in abstract thinking and logical reasoning. Recent large pre-trained language models such as GPT-3 have achieved remarkable progress on mathematical reasoning tasks written in text form, such as math word problems (MWP). However, it is unknown if the models can handle more complex problems that involve math reasoning over heterogeneous information, such as tabular data. To fill the gap, we present Tabular Math Word Problems (TabMWP), a new dataset containing 38,431 open-domain grade-level problems that require mathematical reasoning on both textual and tabular data. Each question in TabMWP is aligned with a tabular context, which is presented as an image, semi-structured text, and a structured table. There are two types of questions: free-text and multi-choice, and each problem is annotated with gold solutions to reveal the multi-step reasoning process. We evaluate different pre-trained models on TabMWP, including the GPT-3 model in a few-shot setting. As earlier studies suggest, since few-shot GPT-3 relies on the selection of in-context examples, its performance is unstable and can degrade to near chance. The unstable issue is more severe when handling complex problems like TabMWP. To mitigate this, we further propose a novel approach, PromptPG, which utilizes policy gradient to learn to select in-context examples from a small amount of training data and then constructs the corresponding prompt for the test example. Experimental results show that our method outperforms the best baseline by 5.31% on the accuracy metric and reduces the prediction variance significantly compared to random selection, which verifies its effectiveness in selecting in-context examples.

[{'version': 'v1', 'created': 'Thu, 29 Sep 2022 08:01:04 GMT'} {'version': 'v2', 'created': 'Wed, 2 Nov 2022 23:42:14 GMT'} {'version': 'v3', 'created': 'Thu, 2 Mar 2023 07:41:55 GMT'}]

2023-03-03

[array(['Lu', 'Pan', ''], dtype=object) array(['Qiu', 'Liang', ''], dtype=object) array(['Chang', 'Kai-Wei', ''], dtype=object) array(['Wu', 'Ying Nian', ''], dtype=object) array(['Zhu', 'Song-Chun', ''], dtype=object) array(['Rajpurohit', 'Tanmay', ''], dtype=object) array(['Clark', 'Peter', ''], dtype=object) array(['Kalyan', 'Ashwin', ''], dtype=object)]

2107.02747

Vincent Caudrelier

Vincent Caudrelier, Nicolas Crampe, Carlos Mbala Dibaya

Nonlinear mirror image method for nonlinear Schr\"odinger equation: Absorption/emission of one soliton by a boundary

38 pages. 5 figures. Authors' version of the published article. Accessiblefrom https://onlinelibrary.wiley.com/doi/10.1111/sapm.12456

10.1111/sapm.12456

nlin.PS hep-th math-ph math.MP nlin.SI

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

We perform the analysis of the focusing nonlinear Schr\"odinger equation on the half-line with time-dependent boundary conditions along the lines of the nonlinear method of images with the help of B\"acklund transformations. The difficulty arising from having such time-dependent boundary conditions at $x=0$ is overcome by changing the viewpoint of the method and fixing the B\"acklund transformation at infinity as well as relating its value at $x=0$ to a time-dependent reflection matrix. The interplay between the various aspects of integrable boundary conditions is reviewed in detail to brush a picture of the area. We find two possible classes of solutions. One is very similar to the case of Robin boundary conditions whereby solitons are reflected at the boundary, as a result of an effective interaction with their images on the other half-line. The new regime of solutions supports the existence of one soliton that is not reflected at the boundary but can be either absorbed or emitted by it. We demonstrate that this is a unique feature of time-dependent integrable boundary conditions.

[{'version': 'v1', 'created': 'Thu, 1 Jul 2021 22:11:01 GMT'} {'version': 'v2', 'created': 'Thu, 21 Oct 2021 21:34:39 GMT'}]

2021-10-25

[array(['Caudrelier', 'Vincent', ''], dtype=object) array(['Crampe', 'Nicolas', ''], dtype=object) array(['Dibaya', 'Carlos Mbala', ''], dtype=object)]

2305.15215

Tao Yu

Tao Yu, Toni J.B. Liu, Albert Tseng, Christopher De Sa

Shadow Cones: Unveiling Partial Orders in Hyperbolic Space

cs.LG

http://creativecommons.org/licenses/by/4.0/

Hyperbolic space has been shown to produce superior low-dimensional embeddings of hierarchical structures that are unattainable in Euclidean space. Building upon this, the entailment cone formulation of Ganea et al. uses geodesically convex cones to embed partial orderings in hyperbolic space. However, these entailment cones lack intuitive interpretations due to their definitions via complex concepts such as tangent vectors and the exponential map in Riemannian space. In this paper, we present shadow cones, an innovative framework that provides a physically intuitive interpretation for defining partial orders on general manifolds. This is achieved through the use of metaphoric light sources and object shadows, inspired by the sun-earth-moon relationship. Shadow cones consist of two primary classes: umbral and penumbral cones. Our results indicate that shadow cones offer robust representation and generalization capabilities across a variety of datasets, such as WordNet and ConceptNet, thereby outperforming the top-performing entailment cones. Our findings indicate that shadow cones offer an innovative, general approach to geometrically encode partial orders, enabling better representation and analysis of datasets with hierarchical structures.

[{'version': 'v1', 'created': 'Wed, 24 May 2023 14:52:56 GMT'}]

2023-05-25

[array(['Yu', 'Tao', ''], dtype=object) array(['Liu', 'Toni J. B.', ''], dtype=object) array(['Tseng', 'Albert', ''], dtype=object) array(['De Sa', 'Christopher', ''], dtype=object)]

0912.4310

James Higbie

J. M. Higbie, S. M. Rochester, B. Patton, R. Holzl\"ohner, D. Bonaccini Calia, and D. Budker

Magnetometry with Mesospheric Sodium

5 pages, 3 figures

physics.atom-ph physics.ao-ph physics.geo-ph

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

Measurement of magnetic fields on the few-hundred-kilometer length scale is significant for a variety of geophysical applications including mapping of crustal magnetism and ocean-circulation measurements, yet available techniques for such measurements are very expensive or of limited accuracy. We propose a scheme for remote detection of magnetic fields using the naturally occurring atomic-sodium-rich layer in the mesosphere and existing high-power lasers developed for laser guide-star applications. The proposed scheme offers dramatic reduction in cost, opening the way to large-scale magnetic mapping missions.

[{'version': 'v1', 'created': 'Tue, 22 Dec 2009 01:27:47 GMT'}]

2009-12-23

[array(['Higbie', 'J. M.', ''], dtype=object) array(['Rochester', 'S. M.', ''], dtype=object) array(['Patton', 'B.', ''], dtype=object) array(['Holzlöhner', 'R.', ''], dtype=object) array(['Calia', 'D. Bonaccini', ''], dtype=object) array(['Budker', 'D.', ''], dtype=object)]

hep-ph/9808295

Dr. Burkhard Kleihaus

B. Kleihaus (NUI Maynooth, Ireland)

Energy barrier in the two-Higgs model

19 pages, including 4 eps figures, LaTex format, new results included

Mod.Phys.Lett. A14 (1999) 1431-1444

10.1142/S021773239900153X

hep-ph hep-th

The electroweak model is extended by a second Higgs doublet and a numerical investigation of static, finite energy classical solutions is performed. The results indicate that for a large domain of the parameters of the Higgs potential, the energy barrier between topologically distinct vacua of the Lagrangian is constituted by a bisphaleron.

[{'version': 'v1', 'created': 'Tue, 11 Aug 1998 15:55:29 GMT'} {'version': 'v2', 'created': 'Thu, 24 Jun 1999 11:55:33 GMT'}]

2009-10-31

[array(['Kleihaus', 'B.', '', 'NUI Maynooth, Ireland'], dtype=object)]

1610.01167

Krista Smith

Krista Lynne Smith, Richard F. Mushotzky, Stuart Vogel, Thomas T. Shimizu, Neal Miller

Radio Properties of the BAT AGN: the FIR-Radio Relation, the Fundamental Plane, and the Main Sequence of Star Formation

17 pages, 9 figures, accepted for publication in the Astrophysical Journal

10.3847/0004-637X/832/2/163

astro-ph.GA

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

We have conducted 22 GHz 1" JVLA imaging of 70 radio-quiet AGN from the Swift-BAT survey. We find radio cores in all but three objects. The radio morphologies of the sample fall into three groups: compact and core-dominated, extended, and jet-like. We spatially decompose each image into core flux and extended flux, and compare the extended radio emission to that predicted from previous Herschel observations using the canonical FIR-radio relation. After removing the AGN contribution to the FIR and radio flux densities, we find that the relation holds remarkably well despite the potentially different star formation physics in the circumnuclear environment. We also compare our core radio flux densities with predictions of coronal models and scale-invariant jet models for the origin of radio emission in radio-quiet AGN, and find general consistency with both models. However, we find that the $L_{\mathrm{R}} / L_{\mathrm{X}}$ relation does not distinguish between star formation and non-relativistic AGN-driven outflows as the origin of radio emission in radio-quiet AGN. Finally, we examine where objects with different radio morphologies fall in relation to the main sequence of star formation, and conclude that those AGN that fall below the main sequence, as X-ray selected AGN have been found to do, have core-dominated or jet-like 22 GHz morphologies.

[{'version': 'v1', 'created': 'Tue, 4 Oct 2016 20:00:18 GMT'}]

2016-12-14

[array(['Smith', 'Krista Lynne', ''], dtype=object) array(['Mushotzky', 'Richard F.', ''], dtype=object) array(['Vogel', 'Stuart', ''], dtype=object) array(['Shimizu', 'Thomas T.', ''], dtype=object) array(['Miller', 'Neal', ''], dtype=object)]

math/0610910

Xueliang Li

Xueliang Li, Jianhua Tu and Zemin Jin

Bipartite Rainbow Numbers of Matchings

8 pages

math.CO

Given two graphs $G$ and $H$, let $f(G,H)$ denote the maximum number $c$ for which there is a way to color the edges of $G$ with $c$ colors such that every subgraph $H$ of $G$ has at least two edges of the same color. Equivalently, any edge-coloring of $G$ with at least $rb(G,H)=f(G,H)+1$ colors contains a rainbow copy of $H$, where a rainbow subgraph of an edge-colored graph is such that no two edges of it have the same color. The number $rb(G,H)$ is called the {\it rainbow number of $H$ with respect to $G$}, and simply called the {\it bipartite rainbow number of $H$} if $G$ is the complete bipartite graph $K_{m,n}$. Erd\H{o}s, Simonovits and S\'{o}s showed that $rb(K_n,K_3)=n$. In 2004, Schiermeyer determined the rainbow numbers $rb(K_n,K_k)$ for all $n\geq k\geq 4$, and the rainbow numbers $rb(K_n,kK_2)$ for all $k\geq 2$ and $n\geq 3k+3$. In this paper we will determine the rainbow numbers $rb(K_{m,n},kK_2)$ for all $k\geq 1$.

[{'version': 'v1', 'created': 'Mon, 30 Oct 2006 02:38:56 GMT'}]

2007-05-23

[array(['Li', 'Xueliang', ''], dtype=object) array(['Tu', 'Jianhua', ''], dtype=object) array(['Jin', 'Zemin', ''], dtype=object)]

2108.06374

Silvia Regina Lopes PhD

J. Stein, S.R.C. Lopes and A.V. Medino

A Generalization of the Ornstein-Uhlenbeck Process: Theoretical Results, Simulations and Parameter Estimation

math.ST stat.TH

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

In this work, we study the class of stochastic process that generalizes the Ornstein-Uhlenbeck processes, hereafter called by \emph{Generalized Ornstein-Uhlenbeck Type Process} and denoted by GOU type process. We consider them driven by the class of noise processes such as Brownian motion, symmetric $\alpha$-stable L\'evy process, a L\'evy process, and even a Poisson process. We give necessary and sufficient conditions under the memory kernel function for the time-stationary and the Markov properties for these processes. When the GOU type process is driven by a L\'evy noise we prove that it is infinitely divisible showing its generating triplet. Several examples derived from the GOU type process are illustrated showing some of their basic properties as well as some time series realizations. These examples also present their theoretical and empirical autocorrelation or normalized codifference functions depending on whether the process has a finite or infinite second moment. We also present the maximum likelihood estimation as well as the Bayesian estimation procedures for the so-called \emph{Cosine process}, a particular process in the class of GOU type processes. For the Bayesian estimation method, we consider the power series representation of Fox's H-function to better approximate the density function of a random variable $\alpha$-stable distributed. We consider four goodness-of-fit tests for helping to decide which \emph{Cosine process} (driven by a Gaussian or an $\alpha$-stable noise) best fit real data sets. Two applications of GOU type model are presented: one based on the Apple company stock market price data and the other based on the cardiovascular mortality in Los Angeles County data.

[{'version': 'v1', 'created': 'Fri, 13 Aug 2021 19:53:36 GMT'}]

2021-08-17

[array(['Stein', 'J.', ''], dtype=object) array(['Lopes', 'S. R. C.', ''], dtype=object) array(['Medino', 'A. V.', ''], dtype=object)]

astro-ph/0208520

Bian Weihao

W. Bian, Y. Zhao

Masses, Accretion Rates and Inclinations of AGNs

9 pages, 9 figures, 4 tables, accepted by A&A

Astron.Astrophys. 395 (2002) 465-474

10.1051/0004-6361:20021319

astro-ph

We assume that the gravitational instability of standard thin accretion disks leads to the Broad Line Regions (BLRs), the B band luminosity comes from standard thin disk and the motion of BLRs is virial. The central black hole masses, the accretion rates and the disk inclinations to the line of sight for 17 Seyfert 1 galaxies and 17 Palomar-Green (PG) quasars have been calculated. Our results are sensitive to $\alpha$ parameter of the standard $\alpha$ disk. With the same values of $\alpha$ ($\alpha=1$), calculated central black hole masses for 17 Seyfert 1 galaxies are consistent with that from Kaspi et al. (2000) while that for 17 PG quasars are larger than that from Kaspi et al. (2000) by almost 2 orders of magnitude. Inclinations of 17 Seyfert 1 galaxies are about 6 times larger than that of 17 PG quasars. These inclinations, with a mean value of $32^{o}$ for 17 Seyfert 1 galaxies that agrees well with the result obtained by fitting the iron $K\alpha$ lines of Seyfert 1 galaxies observed with ASCA (Nandra et al. 1997) and the result obtained by Wu & Han (2001), provide further support for the orientation-dependent unification scheme of active galactic nuclei. There is a relation between the FWHM of H$\beta$ and the inclination, namely the inclination is smaller in AGNs with smaller FWHM of H$\beta$. The effect of inclinations in narrow line Seyfert 1 galaxies (NLS1s) should be considered when one studies the physics of NLS1s. (abbreviated)

[{'version': 'v1', 'created': 'Thu, 29 Aug 2002 02:22:53 GMT'}]

2009-11-07

[array(['Bian', 'W.', ''], dtype=object) array(['Zhao', 'Y.', ''], dtype=object)]

1310.8062

Hsueh-I Lu

Cheng-Wei Lee and Hsueh-I Lu

Replacement Paths via Row Minima of Concise Matrices

23 pages, 1 table, 9 figures, accepted to SIAM Journal on Discrete Mathematics

SIAM Journal on Discrete Mathematics 28(1):206-225, 2014

10.1137/120897146

cs.DS

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

Matrix $M$ is {\em $k$-concise} if the finite entries of each column of $M$ consist of $k$ or less intervals of identical numbers. We give an $O(n+m)$-time algorithm to compute the row minima of any $O(1)$-concise $n\times m$ matrix. Our algorithm yields the first $O(n+m)$-time reductions from the replacement-paths problem on an $n$-node $m$-edge undirected graph (respectively, directed acyclic graph) to the single-source shortest-paths problem on an $O(n)$-node $O(m)$-edge undirected graph (respectively, directed acyclic graph). That is, we prove that the replacement-paths problem is no harder than the single-source shortest-paths problem on undirected graphs and directed acyclic graphs. Moreover, our linear-time reductions lead to the first $O(n+m)$-time algorithms for the replacement-paths problem on the following classes of $n$-node $m$-edge graphs (1) undirected graphs in the word-RAM model of computation, (2) undirected planar graphs, (3) undirected minor-closed graphs, and (4) directed acyclic graphs.

[{'version': 'v1', 'created': 'Wed, 30 Oct 2013 08:20:10 GMT'}]

2014-03-04

[array(['Lee', 'Cheng-Wei', ''], dtype=object) array(['Lu', 'Hsueh-I', ''], dtype=object)]

hep-th/9501061

Chand Devchand

Ch. Devchand and V. Ogievetsky

SELF-DUAL SUPERGRAVITIES

14 pages, latex file

Nucl.Phys. B444 (1995) 381-400

10.1016/0550-3213(95)00139-J

Dubna, JINR-E2-94-384

hep-th

The N-extended supersymmetric self-dual Poincar\'e supergravity equations provide a natural local description of supermanifolds possessing hyperk\"ahler structure. These equations admit an economical formulation in chiral superspace. A reformulation in harmonic superspace encodes self-dual supervielbeins and superconnections in a graded skew-symmetric supermatrix superfield prepotential satisfying generalised Cauchy-Riemann conditions. A recipe is presented for extracting explicit self-dual supervielbeins and superconnections from such `analytic' prepotentials. We demonstrate the method by explicitly decoding a simple example of superfield prepotential, analogous to that corresponding to the Taub-NUT solution. The superspace we thus construct is an interesting $N=2$ supersymmetric deformation of flat space, having flat `body' and constant curvature `soul'.

[{'version': 'v1', 'created': 'Mon, 16 Jan 1995 21:58:41 GMT'}]

2016-09-06

[array(['Devchand', 'Ch.', ''], dtype=object) array(['Ogievetsky', 'V.', ''], dtype=object)]

1603.07022

Alberto Pretto

Marco Imperoli and Alberto Pretto

Active Detection and Localization of Textureless Objects in Cluttered Environments

cs.CV cs.RO

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

This paper introduces an active object detection and localization framework that combines a robust untextured object detection and 3D pose estimation algorithm with a novel next-best-view selection strategy. We address the detection and localization problems by proposing an edge-based registration algorithm that refines the object position by minimizing a cost directly extracted from a 3D image tensor that encodes the minimum distance to an edge point in a joint direction/location space. We face the next-best-view problem by exploiting a sequential decision process that, for each step, selects the next camera position which maximizes the mutual information between the state and the next observations. We solve the intrinsic intractability of this solution by generating observations that represent scene realizations, i.e. combination samples of object hypothesis provided by the object detector, while modeling the state by means of a set of constantly resampled particles. Experiments performed on different real world, challenging datasets confirm the effectiveness of the proposed methods.

[{'version': 'v1', 'created': 'Tue, 22 Mar 2016 22:55:03 GMT'}]

2016-03-24

[array(['Imperoli', 'Marco', ''], dtype=object) array(['Pretto', 'Alberto', ''], dtype=object)]

0907.4093

Michel De Lara

Michel De Lara (CERMICS)

Preferences Yielding the "Precautionary Effect"

q-fin.RM

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

Consider an agent taking two successive decisions to maximize his expected utility under uncertainty. After his first decision, a signal is revealed that provides information about the state of nature. The observation of the signal allows the decision-maker to revise his prior and the second decision is taken accordingly. Assuming that the first decision is a scalar representing consumption, the \emph{precautionary effect} holds when initial consumption is less in the prospect of future information than without (no signal). \citeauthor{Epstein1980:decision} in \citep*{Epstein1980:decision} has provided the most operative tool to exhibit the precautionary effect. Epstein's Theorem holds true when the difference of two convex functions is either convex or concave, which is not a straightforward property, and which is difficult to connect to the primitives of the economic model. Our main contribution consists in giving a geometric characterization of when the difference of two convex functions is convex, then in relating this to the primitive utility model. With this tool, we are able to study and unite a large body of the literature on the precautionary effect.

[{'version': 'v1', 'created': 'Thu, 23 Jul 2009 15:04:52 GMT'}]

2009-07-24

[array(['De Lara', 'Michel', '', 'CERMICS'], dtype=object)]

1905.13675

Yaoxian Song

Song Yaoxian, Cheng Chun, Fei Yuejiao, Li Xiangqing, Yu Changbin

2.5D Image based Robotic Grasping

6 pages, 5 figures, submitted to ANZCC 2019

cs.RO

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

We consider the problem of robotic grasping using depth + RGB information sampling from a real sensor. we design an encoder-decoder neural network to predict grasp policy in real time. This method can fuse the advantage of depth image and RGB image at the same time and is robust for grasp and observation height.We evaluate our method in a physical robotic system and propose an open-loop algorithm to realize robotic grasp operation. We analyze the result of experiment from multi-perspective and the result shows that our method is competitive with the state-of-the-art in grasp performance, real-time and model size. The video is available in https://youtu.be/Wxw_r5a8qV0

[{'version': 'v1', 'created': 'Fri, 31 May 2019 15:31:52 GMT'}]

2019-06-03

[array(['Yaoxian', 'Song', ''], dtype=object) array(['Chun', 'Cheng', ''], dtype=object) array(['Yuejiao', 'Fei', ''], dtype=object) array(['Xiangqing', 'Li', ''], dtype=object) array(['Changbin', 'Yu', ''], dtype=object)]

2006.11847

Muhammad Mustafa

Temadher Alassiry Al-Maadeed, Iqtadar Hussain, Amir Anees, M. T. Mustafa

An image encryption algorithm based on chaotic Lorenz system and novel primitive polynomial S-boxes

cs.CR math.NT math.RA

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

Nowadays, the chaotic cryptosystems are gaining more attention due to their efficiency, the assurance of robustness and high sensitivity corresponding to initial conditions. In literature, on one hand there are many encryption algorithms that only guarantee security while on the other hand there are schemes based on chaotic systems that only promise the uncertainty. Due to these limitations, each of these approaches cannot adequately encounter the challenges of current scenario. Here we take a unified approach and propose an image encryption algorithm based on Lorenz chaotic system and primitive irreducible polynomial S-boxes. First, we propose 16 different S-boxes based on projective general linear group and 16 primitive irreducible polynomials of Galois field of order 256, and then utilize these S-boxes with combination of chaotic map in image encryption scheme. Three chaotic sequences can be produced by the Lorenz chaotic system corresponding to variables $x$, $y$ and $z$. We construct a new pseudo random chaotic sequence $k_i$ based on $x$, $y$ and $z$. The plain image is encrypted by the use of chaotic sequence $k_i$ and XOR operation to get a ciphered image. To demonstrate the strength of presented image encryption, some renowned analyses as well as MATLAB simulations are performed.

[{'version': 'v1', 'created': 'Sun, 21 Jun 2020 16:58:00 GMT'}]

2020-06-23

[array(['Al-Maadeed', 'Temadher Alassiry', ''], dtype=object) array(['Hussain', 'Iqtadar', ''], dtype=object) array(['Anees', 'Amir', ''], dtype=object) array(['Mustafa', 'M. T.', ''], dtype=object)]

2004.05400

Jurriaan Rot

Jurriaan Rot, Bart Jacobs, Paul Levy

Steps and Traces

cs.LO

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

In the theory of coalgebras, trace semantics can be defined in various distinct ways, including through algebraic logics, the Kleisli category of a monad or its Eilenberg-Moore category. This paper elaborates two new unifying ideas: 1) coalgebraic trace semantics is naturally presented in terms of corecursive algebras, and 2) all three approaches arise as instances of the same abstract setting. Our perspective puts the different approaches under a common roof, and allows to derive conditions under which some of them coincide.

[{'version': 'v1', 'created': 'Sat, 11 Apr 2020 13:32:00 GMT'}]

2020-04-14

[array(['Rot', 'Jurriaan', ''], dtype=object) array(['Jacobs', 'Bart', ''], dtype=object) array(['Levy', 'Paul', ''], dtype=object)]

0907.1287

Douglas Rudd

Douglas H. Rudd, Daisuke Nagai

Non-Equilibrium Electrons and the Sunyaev-Zel'dovich Effect of Galaxy Clusters

5 pages, 4 figures, Accepted for publication in ApJL

Astrophys.J.701:L16-L19,2009

10.1088/0004-637X/701/1/L16

astro-ph.CO

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

We present high-resolution cosmological hydrodynamic simulations of three galaxy clusters employing a two-temperature model for the intracluster medium. We show that electron temperatures in cluster outskirts are significantly lower than the mean gas temperature, because Coulomb collisions are insufficient to keep electrons and ions in thermal equilibrium. This deviation is larger in more massive and less relaxed systems, ranging from 5% in relaxed clusters to 30% for clusters undergoing major mergers. The presence of non-equilibrium electrons leads to significant suppression of the SZE signal at large cluster-centric radius. The suppression of the electron pressure also leads to an underestimate of the hydrostatic mass. Merger-driven, internal shocks may also generate significant populations of non-equilibrium electrons in the cluster core, leading to a 5% bias on the integrated SZ mass proxy during cluster mergers.

[{'version': 'v1', 'created': 'Tue, 7 Jul 2009 19:44:16 GMT'}]

2009-08-11

[array(['Rudd', 'Douglas H.', ''], dtype=object) array(['Nagai', 'Daisuke', ''], dtype=object)]

2107.08759

Vincenzo Macr\'i

V. Macr\`i, F. Minganti, A. F. Kockum, A. Ridolfo, S. Savasta and F. Nori

Revealing higher-order light and matter energy exchanges using quantum trajectories in ultrastrong coupling

22 pages, 8 figures

Physical Review A 105, 023720 (2022)

10.1103/PhysRevA.105.023720

quant-ph

http://creativecommons.org/licenses/by/4.0/

The dynamics of open quantum systems is often modelled using master equations, which describe the expected outcome of an experiment (i.e., the average over many realizations of the same dynamics). Quantum trajectories, instead, model the outcome of ideal single experiments -- the ``clicks'' of a perfect detector due to, e.g., spontaneous emission. The correct description of quantum jumps, which are related to random events characterizing a sudden change in the wave function of an open quantum system, is pivotal to the definition of quantum trajectories. In this article, we extend the formalism of quantum trajectories to open quantum systems with ultrastrong coupling (USC) between light and matter by properly defining jump operators in this regime. In such systems, exotic higher-order quantum-state- and energy-transfer can take place without conserving the total number of excitations in the system. The emitted field of such USC systems bears signatures of these higher-order processes, and significantly differs from similar processes at lower coupling strengths. Notably, the emission statistics must be taken at a single quantum trajectory level, since the signatures of these processes are washed out by the ``averaging'' of a master equation. We analyze the impact of the chosen unravelling (i.e., how one collects the output field of the system) for the quantum trajectories and show that these effects of the higher-order USC processes can be revealed in experiments by constructing histograms of detected quantum jumps. We illustrate these ideas by analyzing the excitation of two atoms by a single photon~[Garziano et al., Phys. Rev. Lett.117, 043601 (2016)]. For example, quantum trajectories reveal that keeping track of the quantum jumps from the atoms allow to reconstruct both the oscillations between one photon and two atoms, as well as emerging Rabi oscillations between the two atoms.

[{'version': 'v1', 'created': 'Mon, 19 Jul 2021 11:22:12 GMT'}]

2022-04-11

[array(['Macrì', 'V.', ''], dtype=object) array(['Minganti', 'F.', ''], dtype=object) array(['Kockum', 'A. F.', ''], dtype=object) array(['Ridolfo', 'A.', ''], dtype=object) array(['Savasta', 'S.', ''], dtype=object) array(['Nori', 'F.', ''], dtype=object)]

astro-ph/0402550

Sandip Chakrabarti K.

A. Nandi, S. K. Chakrabarti, S. V. Vadawale and A. R. Rao

Ejection of the inner accretion disk in GRS 1915+105: the magnetic rubber-band effect

7 Latex pages and one figure

Astron.Astrophys. 380 (2001) 245

10.1051/0004-6361:20011444

astro-ph

We examine theoretically the behaviour of the inner accretion disk in GRS 1915+105 when soft X-ray dips are present in the X-ray light curve. We assume the presence of a radial shock in the accretion disk, as in some of the Two Component Advective Flow (TCAF) solutions. We discuss the behaviour of the flux tubes inside a TCAF (which we name Magnetized TCAF or MTCAF model for brevity) and compare various competing forces on the flux tubes. In this MTCAF model, we find that the magnetic tension is the strongest force in a hot plasma of temperature $\gsim 10^{10}$K and as a result, magnetic flux tubes entering in this region collapse catastrophically, thereby occasionally evacuating the inner disk. We postulate that this magnetic `rubber-band' effect induced evacuated disk matter produces the blobby components of outflows and IR/radio jets. We derive the size of the post-shock region by equating the time scale of the Quasi-Periodic Oscillations to the infall time of accreting matter in the post-shock region and found the shock location to be $\sim 45-66 r_g$. We calculate the transition radius $r_{tr}$, where the Keplerian disk deviates into a sub-Keplerian flow, to be $\sim 320r_g$. Based on the derived X-ray spectral parameters, we calculate the mass of this region to be $\sim10^{18}$g. We conclude that during the X-ray dips the matter in the post-shock region, which manifests itself as the thermal-Compton component in the X-ray spectrum, is ejected, along with some sub-Keplerian matter in the pre-shock region.

[{'version': 'v1', 'created': 'Tue, 24 Feb 2004 11:53:45 GMT'}]

2009-11-10

[array(['Nandi', 'A.', ''], dtype=object) array(['Chakrabarti', 'S. K.', ''], dtype=object) array(['Vadawale', 'S. V.', ''], dtype=object) array(['Rao', 'A. R.', ''], dtype=object)]

astro-ph/9902347

Lin Yan

P.J. McCarthy, L. Yan (OCIW), W. Freudling (ECF/ESO), H. Teplitz, E. Malumuth (NASA), R. Weymann(OCIW), M. Malkan (UCLA), R. Fosbury (ECF/ESO), J.Gardner(NASA), L. Storrie-Lombardi(OCIW), R. Thompson(U. Arizona), R. Williams (STScI), S. Heap(NASA)

Emission-Line Galaxies from the NICMOS/HST GRISM Parallel Survey

32 pages, including 6 figures and 4 tables. Accepted for publication in the Astrophysical Journal

10.1086/307491

astro-ph

We present the first results of a survey of random fields with the slitless G141 ($\lambda_c = 1.5\mu, \Delta\lambda=0.8\mu$) grism on NICMOS. Approximately 64 square arcminutes have been observed at intermediate and high galactic latitudes. The 3$\sigma$ limiting line and continuum fluxes in each field vary from $7.5 \times 10^{-17}$ to $1 \times 10^{-17} erg/cm^2/sec$ and from H = 20 to 22, respectively. Our median and area weighted $3\sigma $ limiting line fluxes within a 4 pixel aperture are nearly identical at $4.1 \times 10^{-17} erg/cm^2/sec$ and are 60% deeper than the deepest narrow-band imaging surveys from the ground. We have identified 33 emission-line objects and derive their observed wavelengths, fluxes and equivalent widths. We argue that the most likely line identification is H$\alpha$ and that the redshift range probed is from 0.75 to 1.9. The 2$\sigma$ rest-frame equivalent width limits range from 9\AA to 130\AA with an average of 40\AA. The survey probes an effective co-moving volume of $10^5 h_{50}^{-3} Mpc^3$ for $q_0=0.5$. Our derived co-moving number density of emission line galaxies in the range $0.7 < z < 1.9$ is $3.3\times10^{-4} h_{50}^{3} Mpc^{-3}$, very similar to that of the bright Lyman break objects at $z \sim 3$. The objects with detected emission-lines have a median F160W magnitude of 20.4 (Vega scale) and a median H$\alpha$ luminosity of $2.7 \times 10^{42} erg/sec$. The implied star formation rates range from 1 to 324 M_{\odot}/yr, with an average [NII]6583,6548 corrected rate of 21 M_{\odot}/yr for H_0=50 km/s/Mpc and $q_0=0.5$ (34 M_{\odot}/yr for $q_0=0.1$).

[{'version': 'v1', 'created': 'Thu, 25 Feb 1999 00:23:07 GMT'}]

2009-10-31

[array(['McCarthy', 'P. J.', '', 'OCIW'], dtype=object) array(['Yan', 'L.', '', 'OCIW'], dtype=object) array(['Freudling', 'W.', '', 'ECF/ESO'], dtype=object) array(['Teplitz', 'H.', '', 'NASA'], dtype=object) array(['Malumuth', 'E.', '', 'NASA'], dtype=object) array(['Weymann', 'R.', '', 'OCIW'], dtype=object) array(['Malkan', 'M.', '', 'UCLA'], dtype=object) array(['Fosbury', 'R.', '', 'ECF/ESO'], dtype=object) array(['Gardner', 'J.', '', 'NASA'], dtype=object) array(['Storrie-Lombardi', 'L.', '', 'OCIW'], dtype=object) array(['Thompson', 'R.', '', 'U. Arizona'], dtype=object) array(['Williams', 'R.', '', 'STScI'], dtype=object) array(['Heap', 'S.', '', 'NASA'], dtype=object)]

2012.15126

Dmitri K. Efetov

Petr Stepanov, Ming Xie, Takashi Taniguchi, Kenji Watanabe, Xiaobo Lu, Allan H. MacDonald, B. Andrei Bernevig and Dmitri K. Efetov

Competing zero-field Chern insulators in Superconducting Twisted Bilayer Graphene

10.1103/PhysRevLett.127.197701

cond-mat.mes-hall cond-mat.str-el cond-mat.supr-con

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

The discovery of magic angle twisted bilayer graphene (MATBG) has unveiled a rich variety of superconducting, magnetic and topologically nontrivial phases. The existence of all these phases in one material, and their tunability, has opened new pathways for the creation of unusual gate tunable junctions. However, the required conditions for their creation - gate induced transitions between phases in zero magnetic field - have so far not been achieved. Here, we report on the first experimental demonstration of a device that is both a zero-field Chern insulator and a superconductor. The Chern insulator occurs near moire cell filling factor v = +1 in a hBN non-aligned MATBG device and manifests itself via an anomalous Hall effect. The insulator has Chern number C = +-1 and a relatively high Curie temperature of Tc = 4.5 K. Gate tuning away from this state exposes strong superconducting phases with critical temperatures of up to Tc = 3.5 K. In a perpendicular magnetic field above B > 0.5 T we observe a transition of the /C/= +1 Chern insulator from Chern number C = +-1 to C = 3, characterized by a quantized Hall plateau with Ryx = h/3e2. These observations show that interaction-induced symmetry breaking in MATBG leads to zero-field ground states that include almost degenerate and closely competing Chern insulators, and that states with larger Chern numbers couple most strongly to the B-field. By providing the first demonstration of a system that allows gate-induced transitions between magnetic and superconducting phases, our observations mark a major milestone in the creation of a new generation of quantum electronics.

[{'version': 'v1', 'created': 'Wed, 30 Dec 2020 11:59:56 GMT'}]

2021-11-17

[array(['Stepanov', 'Petr', ''], dtype=object) array(['Xie', 'Ming', ''], dtype=object) array(['Taniguchi', 'Takashi', ''], dtype=object) array(['Watanabe', 'Kenji', ''], dtype=object) array(['Lu', 'Xiaobo', ''], dtype=object) array(['MacDonald', 'Allan H.', ''], dtype=object) array(['Bernevig', 'B. Andrei', ''], dtype=object) array(['Efetov', 'Dmitri K.', ''], dtype=object)]

1410.4899

Xubing Tang Dr.

Xubing Tang, Fang Gao, Yaoxiong Wan, Jianguang Wu, Feng Shuang

Non-Gaussian features from Excited Squeezed Vacuum State

17 pages, 5 figures

10.1016/j.optcom.2015.01.053

quant-ph

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

In this work, we introduce a non-Gaussian quantum state named excited squeezed vacuum state (ESVS), which can be ustilized to describe quantum light field emitted from the multiphoton quantum process occurred in some restricted quantum systems. We investigate its nonclassical properties such as Wigner distribution in phase space, photon number distribution, the second-order autocorrelation and the quadrature fluctuations. By virtue of the Hilbert-Schmidt distance method, we quantify the non-Gaussianity of the ESVS. Due to the similar photon statistics, we examine the fidelity between the ESVS and the photon-subtraction squeezed vacuum state (PSSVS), and then find the optimal fidelity by monitoring the relevant parameters.

[{'version': 'v1', 'created': 'Sat, 18 Oct 2014 02:24:29 GMT'}]

2015-06-23

[array(['Tang', 'Xubing', ''], dtype=object) array(['Gao', 'Fang', ''], dtype=object) array(['Wan', 'Yaoxiong', ''], dtype=object) array(['Wu', 'Jianguang', ''], dtype=object) array(['Shuang', 'Feng', ''], dtype=object)]

0805.4738

Joakim Arnlind

Jens Hoppe

U(1) invariant Membranes and Singularities

6 pages

hep-th

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

A formulation of U(1) - symmetric classical membrane motions (preserving one rotational symmetry) is given, and reductions to systems of ODE's, as well as some ideas concerning singularities and integrability.

[{'version': 'v1', 'created': 'Fri, 30 May 2008 12:18:08 GMT'}]

2008-06-02

[array(['Hoppe', 'Jens', ''], dtype=object)]

1407.6290

Naser Alajmi Mr

Naser Alajmi

Wireless Sensor Networks Attacks and Solutions

4 pages, 3 figures

cs.CR

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

A few years ago, wireless sensor networks (WSNs) used by only military. Now, we have seen many of organizations use WSNs for some purposes such as weather, pollution, traffic control, and healthcare. Security is becoming on these days a major concern for wireless sensor network. In this paper I focus on the security types of attacks and their detection. This paper anatomizes the security requirements and security attacks in wireless sensor networks. Also, indicate to the benchmarks for the security in WSNs.

[{'version': 'v1', 'created': 'Wed, 23 Jul 2014 16:50:42 GMT'}]

2014-07-24

[array(['Alajmi', 'Naser', ''], dtype=object)]

1104.4998

Pavlo Pylyavskyy

Thomas Lam, Pavlo Pylyavskyy

Inverse problem in cylindrical electrical networks

22 pages, 15 figures

math.CO

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

In this paper we study the inverse Dirichlet-to-Neumann problem for certain cylindrical electrical networks. We define and study a birational transformation acting on cylindrical electrical networks called the electrical $R$-matrix. We use this transformation to formulate a general conjectural solution to this inverse problem on the cylinder. This conjecture extends work of Curtis, Ingerman, and Morrow, and of de Verdi\`ere, Gitler, and Vertigan for circular planar electrical networks. We show that our conjectural solution holds for certain "purely cylindrical" networks. Here we apply the grove combinatorics introduced by Kenyon and Wilson.

[{'version': 'v1', 'created': 'Tue, 26 Apr 2011 19:24:49 GMT'}]

2011-04-27

[array(['Lam', 'Thomas', ''], dtype=object) array(['Pylyavskyy', 'Pavlo', ''], dtype=object)]

2104.07886

Yingtong Dou

Hao Peng, Ruitong Zhang, Yingtong Dou, Renyu Yang, Jingyi Zhang, Philip S. Yu

Reinforced Neighborhood Selection Guided Multi-Relational Graph Neural Networks

Accepted by ACM TOIS. Code is available at https://github.com/safe-graph/RioGNN

cs.LG cs.SI

http://creativecommons.org/licenses/by/4.0/

Graph Neural Networks (GNNs) have been widely used for the representation learning of various structured graph data. While promising, most existing GNNs oversimplified the complexity and diversity of the edges in the graph, and thus inefficient to cope with ubiquitous heterogeneous graphs, which are typically in the form of multi-relational graph representations. In this paper, we propose RioGNN, a novel Reinforced, recursive and flexible neighborhood selection guided multi-relational Graph Neural Network architecture, to navigate complexity of neural network structures whilst maintaining relation-dependent representations. We first construct a multi-relational graph, according to the practical task, to reflect the heterogeneity of nodes, edges, attributes and labels. To avoid the embedding over-assimilation among different types of nodes, we employ a label-aware neural similarity measure to ascertain the most similar neighbors based on node attributes. A reinforced relation-aware neighbor selection mechanism is developed to choose the most similar neighbors of a targeting node within a relation before aggregating all neighborhood information from different relations to obtain the eventual node embedding. Particularly, to improve the efficiency of neighbor selecting, we propose a new recursive and scalable reinforcement learning framework with estimable depth and width for different scales of multi-relational graphs. RioGNN can learn more discriminative node embedding with enhanced explainability due to the recognition of individual importance of each relation via the filtering threshold mechanism. Comprehensive experiments on real-world graph data and practical tasks demonstrate the advancements of effectiveness, efficiency and the model explainability, as opposed to other comparative GNN models.

[{'version': 'v1', 'created': 'Fri, 16 Apr 2021 04:30:06 GMT'} {'version': 'v2', 'created': 'Tue, 5 Oct 2021 21:20:31 GMT'}]

2021-10-07

[array(['Peng', 'Hao', ''], dtype=object) array(['Zhang', 'Ruitong', ''], dtype=object) array(['Dou', 'Yingtong', ''], dtype=object) array(['Yang', 'Renyu', ''], dtype=object) array(['Zhang', 'Jingyi', ''], dtype=object) array(['Yu', 'Philip S.', ''], dtype=object)]

2208.12952

Lijun Xia

Lijun Xia, Liangliang Lu, Kun Wang, Xinhe Jiang, Shining Zhu and Xiaosong Ma

Experimental optimal verification of three-dimensional entanglement on a silicon chip

10.1088/1367-2630/ac8a67

quant-ph physics.optics

http://creativecommons.org/licenses/by-nc-nd/4.0/

High-dimensional entanglement is significant for the fundamental studies of quantum physics and offers unique advantages in various quantum information processing (QIP) tasks. Integrated quantum devices have recently emerged as a promising platform for creating, processing, and detecting complex high-dimensional entangled states. A crucial step towards practical quantum technologies is to verify that these devices work reliably with an optimal strategy. In this work, we experimentally implement an optimal quantum verification strategy on a three-dimensional maximally entangled state using local projective measurements on a silicon photonic chip. A 95% confidence is achieved from 1190 copies to verify the target quantum state. The obtained scaling of infidelity as a function of the number of copies is -0.5497+-0.0002, exceeding the standard quantum limit of -0.5 with 248 standard deviations. Our results indicate that quantum state verification could serve as an efficient tool for complex quantum measurement tasks.

[{'version': 'v1', 'created': 'Sat, 27 Aug 2022 07:45:21 GMT'}]

2022-08-30

[array(['Xia', 'Lijun', ''], dtype=object) array(['Lu', 'Liangliang', ''], dtype=object) array(['Wang', 'Kun', ''], dtype=object) array(['Jiang', 'Xinhe', ''], dtype=object) array(['Zhu', 'Shining', ''], dtype=object) array(['Ma', 'Xiaosong', ''], dtype=object)]

1110.1777

Takahiro Hatano

Takahiro Hatano, Cl\'ement Narteau, Peter Shebalin

Common dependence on stress for the statistics of granular avalanches and earthquakes

4 pages

Scientific Reports 5, 12280 (2015)

10.1038/srep12280

cond-mat.stat-mech physics.geo-ph

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

The statistical properties of avalanches in a dissipative particulate system under slow shear are investigated using molecular dynamics simulations. It is found that the magnitude-frequency distribution obeys the Gutenberg-Richter law only in the proximity of a critical density and that the exponent is sensitive to the minute changes in density. It is also found that aftershocks occur in this system with a decay rate that follows the Modified Omori law. We show that the exponent of the magnitude-frequency distribution and the time constant of the Modified Omori law are decreasing functions of the shear stress. The dependences of these two parameters on shear stress coincide with recent seismological observations [D. Schorlemmer et al. Nature 437, 539 (2005); C. Narteau et al. Nature 462, 642 (2009)].

[{'version': 'v1', 'created': 'Sat, 8 Oct 2011 23:56:29 GMT'}]

2015-07-31

[array(['Hatano', 'Takahiro', ''], dtype=object) array(['Narteau', 'Clément', ''], dtype=object) array(['Shebalin', 'Peter', ''], dtype=object)]

1508.07573

Vladimir Khatsymovsky

V.M. Khatsymovsky

First order minisuperspace model for the Faddeev formulation of gravity

12 pages, 1 figure, to appear in Mod. Phys. Lett. A

Mod. Phys. Lett. A, Vol. 30, No. 32 (2015) 1550172

10.1142/S0217732315501746

gr-qc

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

Faddeev formulation of general relativity (GR) is considered where the metric is composed of ten vector fields or a ten-dimensional tetrad. Upon partial use of the field equations, this theory results in the usual GR. Earlier we have proposed some minisuperspace model for the Faddeev formulation where the tetrad fields are piecewise constant on the polytopes like 4-simplices or, say, cuboids into which ${\rm I \hspace{-3pt} R}^4$ can be decomposed. Now we study some representation of this (discrete) theory, an analogue of the Cartan-Weyl connection-type form of the Hilbert-Einstein action in the usual continuum GR.

[{'version': 'v1', 'created': 'Sun, 30 Aug 2015 13:56:31 GMT'}]

2015-09-28

[array(['Khatsymovsky', 'V. M.', ''], dtype=object)]

1109.2836

Kailash Misra

Kailash C. Misra, Masato Okado, and Evan A. Wilson

Soliton cellular automaton associated with $G_2^{(1)}$ crystal base

10.1063/1.3673541

math.QA math-ph math.MP

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

We calculate the combinatorial $R$ matrix for all elements of $\mathcal{B}_l\otimes \mathcal{B}_1$ where $\mathcal{B}_l$ denotes the $G_2^{(1)}$-perfect crystal of level $l$, and then study the soliton cellular automaton constructed from it. The solitons of length $l$ are identified with elements of the $A_1^{(1)}$-crystal $\tilde{\mathcal{B}}_{3l}$. The scattering rule for our soliton cellular automaton is identified with the combinatorial $R$ matrix for $A_1^{(1)}$-crystals.

[{'version': 'v1', 'created': 'Tue, 13 Sep 2011 16:08:17 GMT'}]

2015-05-30

[array(['Misra', 'Kailash C.', ''], dtype=object) array(['Okado', 'Masato', ''], dtype=object) array(['Wilson', 'Evan A.', ''], dtype=object)]