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2111.07542

Marius Hofert

Erik Hintz, Marius Hofert, Christiane Lemieux, Yoshihiro Taniguchi

Single-Index Importance Sampling with Stratification

stat.CO

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

In many stochastic problems, the output of interest depends on an input random vector mainly through a single random variable (or index) via an appropriate univariate transformation of the input. We exploit this feature by proposing an importance sampling method that makes rare events more likely by changing the distribution of the chosen index. Further variance reduction is guaranteed by combining this single-index importance sampling approach with stratified sampling. The dimension-reduction effect of single-index importance sampling also enhances the effectiveness of quasi-Monte Carlo methods. The proposed method applies to a wide range of financial or risk management problems. We demonstrate its efficiency for estimating large loss probabilities of a credit portfolio under a normal and t-copula model and show that our method outperforms the current standard for these problems.

[{'version': 'v1', 'created': 'Mon, 15 Nov 2021 05:28:34 GMT'}]

2021-11-16

[array(['Hintz', 'Erik', ''], dtype=object) array(['Hofert', 'Marius', ''], dtype=object) array(['Lemieux', 'Christiane', ''], dtype=object) array(['Taniguchi', 'Yoshihiro', ''], dtype=object)]

1704.04670

Vladimir V. Sergeichuk

Andrii Dmytryshyn, Vyacheslav Futorny, Tetiana Klymchuk, Vladimir V. Sergeichuk

Generalization of Roth's solvability criteria to systems of matrix equations

11 pages

Linear Algebra Appl. 527 (2017) 294-302

10.1016/j.laa.2017.04.011

math.RT

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

W.E. Roth (1952) proved that the matrix equation $AX-XB=C$ has a solution if and only if the matrices $\left[\begin{matrix}A&C\\0&B\end{matrix}\right]$ and $\left[\begin{matrix}A&0\\0&B\end{matrix}\right]$ are similar. A. Dmytryshyn and B. K{\aa}gstr\"om (2015) extended Roth's criterion to systems of matrix equations $A_iX_{i'}M_i-N_iX_{i''}^{\sigma_i} B_i=C_i$ $(i=1,\dots,s)$ with unknown matrices $X_1,\dots,X_t$, in which every $X^{\sigma}$ is $X$, $X^T$, or $X^*$. We extend their criterion to systems of complex matrix equations that include the complex conjugation of unknown matrices. We also prove an analogous criterion for systems of quaternion matrix equations.

[{'version': 'v1', 'created': 'Sat, 15 Apr 2017 18:02:20 GMT'}]

2017-04-18

[array(['Dmytryshyn', 'Andrii', ''], dtype=object) array(['Futorny', 'Vyacheslav', ''], dtype=object) array(['Klymchuk', 'Tetiana', ''], dtype=object) array(['Sergeichuk', 'Vladimir V.', ''], dtype=object)]

2105.02745

Ingve Simonsen

Ver\'onica P. Simonsen, Dick Bedeaux, and Ingve Simonsen

Non-parametric reconstruction of the statistical properties of penetrable, isotropic randomly rough surfaces from in-plane, co-polarized light scattering data: Application to computer generated and experimental scattering data

23 pages, 9 figures

Phys. Rev. A 104, 043502 (2021)

10.1103/PhysRevA.104.043502

physics.optics physics.app-ph physics.class-ph

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

An approach is introduced for the non-parametric reconstruction of the statistical properties of penetrable, isotropic randomly rough surfaces from in-plane, co-polarized light scattering data. Starting from expressions within the Kirchhoff approximation for the light scattered diffusely by a two-dimensional randomly rough surface, an analytic expression for the normalized surface height correlation function is obtained as an integral over the in-plane and co-polarized scattering data with the introduction of only a couple of additional approximations. The inversion approach consists of two main steps. In the first step the surface roughness is estimated. Next, this value is used to obtain the functional form of the surface height correlation function without initially assuming any particular form for this function (non-parametric inversion). The input data used in validating this inversion approach consist of in-plane and co-polarized scattering data obtained for different forms of the correlation function by either computer simulations or by experiments for two-dimensional randomly rough dielectric or metallic surfaces. Good agreement was obtained between the correlation function and surface roughness obtained during the reconstruction and the corresponding quantities assumed when generating the input scattering data; this was the case for both dielectric and metallic surfaces, for both p- and s-polarized light, and for different polar angles of incidence. The proposed inversion approach provides an accurate, efficient, robust and contact-less method based on in-plane and co-polarized scattering data for the non-parametric characterization of the statistical properties of isotropic two-dimensional randomly rough dielectric and metallic surface.

[{'version': 'v1', 'created': 'Thu, 6 May 2021 15:14:22 GMT'}]

2021-10-13

[array(['Simonsen', 'Verónica P.', ''], dtype=object) array(['Bedeaux', 'Dick', ''], dtype=object) array(['Simonsen', 'Ingve', ''], dtype=object)]

1401.4531

Esa Vasili Vesalainen

Esa V. Vesalainen

Rellich Type Theorems for Unbounded Domains

Inverse Problems and Imaging, 8 (2014), 865--883

10.3934/ipi.2014.8.865

math.AP

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

We give several generalizations of Rellich's classical uniqueness theorem to unbounded domains. We give a natural half-space generalization for super-exponentially decaying inhomogeneities using real variable techniques. We also prove under super-exponential decay a discrete generalization where the inhomogeneity only needs to vanish in a suitable cone. The more traditional complex variable techniques are used to prove the half-space result again, but with less exponential decay, and a variant with polynomial decay, but with supports exponentially thin at infinity. As an application, we prove the discreteness of non-scattering energies for non-compactly supported potentials with suitable asymptotic behaviours and supports.

[{'version': 'v1', 'created': 'Sat, 18 Jan 2014 11:25:17 GMT'}]

2014-09-02

[array(['Vesalainen', 'Esa V.', ''], dtype=object)]

1708.02371

Alper Atamturk

Alper Atamturk, Carlos Deck and Hyemin Jeon

Successive Quadratic Upper-Bounding for Discrete Mean-Risk Minimization and Network Interdiction

BCOL Research Report 17.05, IEOR, UC Berkeley

math.OC

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

The advances in conic optimization have led to its increased utilization for modeling data uncertainty. In particular, conic mean-risk optimization gained prominence in probabilistic and robust optimization. Whereas the corresponding conic models are solved efficiently over convex sets, their discrete counterparts are intractable. In this paper, we give a highly effective successive quadratic upper-bounding procedure for discrete mean-risk minimization problems. The procedure is based on a reformulation of the mean-risk problem through the perspective of its convex quadratic term. Computational experiments conducted on the network interdiction problem with stochastic capacities show that the proposed approach yields solutions within 1-2% of optimality in a small fraction of the time required by exact search algorithms. We demonstrate the value of the proposed approach for constructing efficient frontiers of flow-at-risk vs. interdiction cost for varying confidence levels.

[{'version': 'v1', 'created': 'Tue, 8 Aug 2017 04:54:37 GMT'} {'version': 'v2', 'created': 'Sat, 25 Aug 2018 18:37:15 GMT'}]

2018-08-28

[array(['Atamturk', 'Alper', ''], dtype=object) array(['Deck', 'Carlos', ''], dtype=object) array(['Jeon', 'Hyemin', ''], dtype=object)]

2211.04869

Andrew Bragg

Yan Zhang, Guiquan Wang, Andrew D Bragg

Asymptotic closure model for inertial particle transport in turbulent boundary layers

physics.flu-dyn

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

Transport equations for heavy inertial particles in turbulent boundary layers may be derived from an underlying phase-space probability density function (PDF) equation. These equations, however, are unclosed, and the standard closure approach is to use a quasi-Normal approximation (QNA) in which the fourth moments are approximated as behaving as if the velocities were Normally distributed. Except for particles with weak inertia, the QNA leads to large quantitative errors, and is not consistent with the known asymptotic predictions of Sikovsky (Flow Turbulence Combust, vol. 92, 2014, pp. 41-64) for the moments of the PDF in the viscous sublayer. We derive a new closure approximation based on an asymptotic solution to the transport equations in regions where the effect of particle inertia is significant. The new closure is consistent with the asymptotic predictions of Sikovsky, but applies even outside the viscous sublayer. Comparisons with direct numerical simulations (DNS) show that the new closure gives similar results to the QNA (with the QNA results in slightly better agreement with the DNS) when the viscous Stokes number is $St<10$, but for $St>10$ the new model is in far better agreement with the DNS than the QNA. While the predictions from the new model leave room for improvement, the results suggest that this new closure strategy is a very effective alternative to the traditional QNA approach, and the closure could be refined in future work.

[{'version': 'v1', 'created': 'Wed, 9 Nov 2022 13:24:47 GMT'}]

2022-11-10

[array(['Zhang', 'Yan', ''], dtype=object) array(['Wang', 'Guiquan', ''], dtype=object) array(['Bragg', 'Andrew D', ''], dtype=object)]

2209.10043

Michael Yao

Michael S. Yao, Allison Chae, Matthew T. MacLean, Anurag Verma, Jeffrey Duda, James Gee, Drew A. Torigian, Daniel Rader, Charles Kahn, Walter R. Witschey, Hersh Sagreiya

Learning-Based Radiomic Prediction of Type 2 Diabetes Mellitus Using Image-Derived Phenotypes

9 pages

cs.LG cs.AI eess.IV q-bio.QM

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

Early diagnosis of Type 2 Diabetes Mellitus (T2DM) is crucial to enable timely therapeutic interventions and lifestyle modifications. As medical imaging data become more widely available for many patient populations, we sought to investigate whether image-derived phenotypic data could be leveraged in tabular learning classifier models to predict T2DM incidence without the use of invasive blood lab measurements. We show that both neural network and decision tree models that use image-derived phenotypes can predict patient T2DM status with recall scores as high as 87.6%. We also propose the novel use of these same architectures as 'SynthA1c encoders' that are able to output interpretable values mimicking blood hemoglobin A1C empirical lab measurements. Finally, we demonstrate that T2DM risk prediction model sensitivity to small perturbations in input vector components can be used to predict performance on covariates sampled from previously unseen patient populations.

[{'version': 'v1', 'created': 'Tue, 20 Sep 2022 23:39:52 GMT'}]

2022-09-22

[array(['Yao', 'Michael S.', ''], dtype=object) array(['Chae', 'Allison', ''], dtype=object) array(['MacLean', 'Matthew T.', ''], dtype=object) array(['Verma', 'Anurag', ''], dtype=object) array(['Duda', 'Jeffrey', ''], dtype=object) array(['Gee', 'James', ''], dtype=object) array(['Torigian', 'Drew A.', ''], dtype=object) array(['Rader', 'Daniel', ''], dtype=object) array(['Kahn', 'Charles', ''], dtype=object) array(['Witschey', 'Walter R.', ''], dtype=object) array(['Sagreiya', 'Hersh', ''], dtype=object)]

1202.2001

Marcoen Cabbolet

Marcoen J.T.F. Cabbolet, Harrie C.M. de Swart

Set Matrix Theory as a Physically Motivated Generalization of Zermelo-Fraenkel Set Theory

16 pages; based on the third chapter (pp. 23-52) of the first author's dissertation, entitled "Elementary Process Theory: axiomatic introduction and applications" (Vrije Universiteit Brussel, 2011)

Logique et Analyse 225, 59-82 (2014)

math.LO

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

Recently, the Elementary Process Theory (EPT) has been developed as a set of fundamental principles that might underlie a gravitational repulsion of matter and antimatter. This paper presents set matrix theory (SMT) as the foundation of the mathematical-logical framework in which the EPT has been formalized: Zermelo-Fraenkel set theory (ZF), namely, cannot be used as such. SMT is a generalization of ZF: whereas ZF uses only sets as primitive objects, in the framework of SMT finite matrices with set-valued entries are objects sui generis, with a one-by-one set matrix [x] being identical to the set x. It is proved that every set that can be constructed in ZF can also be constructed in SMT: as a mathematical foundation, SMT is thus not weaker than ZF. In addition, it is shown that SMT is more suitable han ZF for the intended application to physics. The conclusion is that SMT, contrary to ZF, is acceptable as the mathematical-logical foundation of the framework for physics that is determined by the EPT.

[{'version': 'v1', 'created': 'Thu, 9 Feb 2012 14:41:31 GMT'} {'version': 'v2', 'created': 'Wed, 30 Jan 2013 21:57:15 GMT'}]

2014-01-16

[array(['Cabbolet', 'Marcoen J. T. F.', ''], dtype=object) array(['de Swart', 'Harrie C. M.', ''], dtype=object)]

1309.3680

Robert Penna

Robert F. Penna, Akshay Kulkarni, Ramesh Narayan

A new equilibrium torus solution and GRMHD initial conditions

8 pages, 4 figures, A&A accepted

10.1051/0004-6361/201219666

astro-ph.HE

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

General relativistic magnetohydrodynamic (GRMHD) simulations are providing influential models for black hole spin measurements, gamma ray bursts, and supermassive black hole feedback. Many of these simulations use the same initial condition: a rotating torus of fluid in hydrostatic equilibrium. A persistent concern is that simulation results sometimes depend on arbitrary features of the initial torus. For example, the Bernoulli parameter (which is related to outflows), appears to be controlled by the Bernoulli parameter of the initial torus. In this paper, we give a new equilibrium torus solution and describe two applications for the future. First, it can be used as a more physical initial condition for GRMHD simulations than earlier torus solutions. Second, it can be used in conjunction with earlier torus solutions to isolate the simulation results that depend on initial conditions. We assume axisymmetry, an ideal gas equation of state, constant entropy, and ignore self-gravity. We fix an angular momentum distribution and solve the relativistic Euler equations in the Kerr metric. The Bernoulli parameter, rotation rate, and geometrical thickness of the torus can be adjusted independently. Our torus tends to be more bound and have a larger radial extent than earlier torus solutions. While this paper was in preparation, several GRMHD simulations appeared based on our equilibrium torus. We believe it will continue to provide a more realistic starting point for future simulations.

[{'version': 'v1', 'created': 'Sat, 14 Sep 2013 15:29:55 GMT'}]

2015-06-17

[array(['Penna', 'Robert F.', ''], dtype=object) array(['Kulkarni', 'Akshay', ''], dtype=object) array(['Narayan', 'Ramesh', ''], dtype=object)]

1304.1941

Manabu Machida

Manabu Machida

Singular eigenfunctions for the three-dimensional radiative transport equation

10.1364/JOSAA.31.000067

math-ph math.MP physics.optics

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

Case's method obtains solutions to the radiative transport equation as superpositions of elementary solutions when the specific intensity depends on one spatial variable. In this paper, we find elementary solutions when the specific intensity depends on three spatial variables in three-dimensional space. By using the reference frame whose z-axis lies in the direction of the wave vector, the angular part of each elementary solution becomes the singular eigenfunction for the one-dimensional radiative transport equation. Thus Case's method is generalized.

[{'version': 'v1', 'created': 'Sat, 6 Apr 2013 22:18:04 GMT'} {'version': 'v2', 'created': 'Sat, 7 Sep 2013 15:06:52 GMT'}]

2015-06-15

[array(['Machida', 'Manabu', ''], dtype=object)]

2001.01713

Chaim Even-Zohar

Chaim Even-Zohar, Michael Farber

Random Surfaces with Boundary

Discrete & Computational Geometry, online, 2021

10.1007/s00454-021-00301-8

math.CO math.GT

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

A surface with boundary is randomly generated by gluing polygons along some of their sides. We show that its genus and number of boundary components asymptotically follow a bivariate normal distribution.

[{'version': 'v1', 'created': 'Mon, 6 Jan 2020 18:56:06 GMT'} {'version': 'v2', 'created': 'Fri, 5 Mar 2021 14:26:25 GMT'}]

2021-04-21

[array(['Even-Zohar', 'Chaim', ''], dtype=object) array(['Farber', 'Michael', ''], dtype=object)]

2112.12075

Mahouton Norbert Hounkonnou

Jian Cao, Sama Arjika and Mahouton Norbert Hounkonnou

Generalized q-difference equations for general q-polynomials with double q-binomial coefficients

math.CO

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

In this paper, we use the generalized q-polynomials with double q-binomial coefficients and homogeneous q-operators [J. Difference Equ. Appl. 20 (2014), 837--851.] to construct q-difference equations with seven variables, which generalize recent works of Jia et al [Symmetry 2021, 13, 1222.]. In addition, we derive Rogers formulas, extended Rogers formulas and Srivastava--Agarwal type bilinear generating functions for generalized q-polynomials, which generalize generating functions for Cigler's polynomials [J. Difference Equ. Appl. 24 (2018), 479--502.]. Finally, we also derive mixed generating functions using q-difference equations.

[{'version': 'v1', 'created': 'Fri, 17 Dec 2021 19:52:28 GMT'}]

2021-12-23

[array(['Cao', 'Jian', ''], dtype=object) array(['Arjika', 'Sama', ''], dtype=object) array(['Hounkonnou', 'Mahouton Norbert', ''], dtype=object)]

1707.02787

Myoung-Sun Heo

Geol Moon, Myoung-Sun Heo, Yonghee Kim, Heung-Ryoul Noh, Wonho Jhe

Nonlinear, Nonequilibrium and Collective Dynamics in a Periodically Modulated Cold Atom System

57 pages, 25 figures

10.1016/j.physrep.2017.07.002

physics.atom-ph cond-mat.quant-gas cond-mat.stat-mech

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

The physics of critical phenomena in a many-body system far from thermal equilibrium is an interesting and important issue to be addressed both experimentally and theoretically. The trapped cold atoms have been actively used as a clean and versatile simulator for classical and quantum-mechanical systems, deepening understanding of the many-body physics behind. Here we review the nonlinear and collective dynamics in a periodically modulated magneto-optically trapped cold atoms. By temporally modulating the intensity of the trapping lasers with the controlled phases, one can realize two kinds of nonlinear oscillators, the parametrically driven oscillator and the resonantly driven Duffing oscillator, which exhibit the dynamical bistable states. Cold atoms behave not only as the single-particle nonlinear oscillators, but also as the coupled oscillators by the light-induced inter-atomic interaction, which leads to the phase transitions far from equilibrium in a way similar to the phase transition in equilibrium. The parametrically driven cold atoms show the ideal mean-field symmetry-breaking transition, and the symmetry is broken with respect to time translation by the modulation period. Such a phase transition results from the cooperation and competition between the inter-particle interaction and the fluctuations, which lead to the nonlinear switching of atoms between the vibrational states, and the experimentally measured critical characteristics prove it as the ideal mean-field transition class. On the other hand, the resonantly driven cold atoms that possess the coexisting periodic attractors exhibit the kinetic phase transition analogous to the discontinuous gas-liquid phase transition in equilibrium, and interestingly the global interaction between atoms causes the shift of the phase-transition boundary.

[{'version': 'v1', 'created': 'Mon, 10 Jul 2017 10:22:57 GMT'}]

2017-09-13

[array(['Moon', 'Geol', ''], dtype=object) array(['Heo', 'Myoung-Sun', ''], dtype=object) array(['Kim', 'Yonghee', ''], dtype=object) array(['Noh', 'Heung-Ryoul', ''], dtype=object) array(['Jhe', 'Wonho', ''], dtype=object)]

2101.02504

Stephen DiAdamo

Stephen DiAdamo, Marco Ghibaudi, James Cruise

Distributed Quantum Computing and Network Control for Accelerated VQE

This work has been submitted to the IEEE for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessible

IEEE Transactions on Quantum Engineering 2021

10.1109/TQE.2021.3057908

quant-ph cs.SY eess.SY

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

Interconnecting small quantum computers will be essential in the future for creating large scale, robust quantum computers. Methods for distributing monolithic quantum algorithms efficiently are thus needed. In this work we consider an approach for distributing the accelerated variational quantum eigensolver (AVQE) algorithm over arbitrary sized - in terms of number of qubits - distributed quantum computers. We consider approaches for distributing qubit assignments of the Ansatz states required to estimate the expectation value of Hamiltonian operators in quantum chemistry in a parallelized computation and provide a systematic approach to generate distributed quantum circuits for distributed quantum computing. Moreover, we propose an architecture for a distributed quantum control system in the settings of centralized and decentralized network control.

[{'version': 'v1', 'created': 'Thu, 7 Jan 2021 11:50:24 GMT'}]

2021-03-22

[array(['DiAdamo', 'Stephen', ''], dtype=object) array(['Ghibaudi', 'Marco', ''], dtype=object) array(['Cruise', 'James', ''], dtype=object)]

2007.11849

Chen-Yu Wei

Chen-Yu Wei, Mehdi Jafarnia-Jahromi, Haipeng Luo, Rahul Jain

Learning Infinite-horizon Average-reward MDPs with Linear Function Approximation

cs.LG stat.ML

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

We develop several new algorithms for learning Markov Decision Processes in an infinite-horizon average-reward setting with linear function approximation. Using the optimism principle and assuming that the MDP has a linear structure, we first propose a computationally inefficient algorithm with optimal $\widetilde{O}(\sqrt{T})$ regret and another computationally efficient variant with $\widetilde{O}(T^{3/4})$ regret, where $T$ is the number of interactions. Next, taking inspiration from adversarial linear bandits, we develop yet another efficient algorithm with $\widetilde{O}(\sqrt{T})$ regret under a different set of assumptions, improving the best existing result by Hao et al. (2020) with $\widetilde{O}(T^{2/3})$ regret. Moreover, we draw a connection between this algorithm and the Natural Policy Gradient algorithm proposed by Kakade (2002), and show that our analysis improves the sample complexity bound recently given by Agarwal et al. (2020).

[{'version': 'v1', 'created': 'Thu, 23 Jul 2020 08:23:44 GMT'} {'version': 'v2', 'created': 'Mon, 26 Apr 2021 09:12:03 GMT'}]

2021-04-27

[array(['Wei', 'Chen-Yu', ''], dtype=object) array(['Jafarnia-Jahromi', 'Mehdi', ''], dtype=object) array(['Luo', 'Haipeng', ''], dtype=object) array(['Jain', 'Rahul', ''], dtype=object)]

1511.02861

Megan Shabram

Megan Shabram, Brice-Olivier Demory, Jessi Cisewski, Eric B. Ford, Leslie Rogers

The Eccentricity Distribution of Short-Period Planet Candidates Detected by Kepler in Occultation

Accepted for publication in ApJ

10.3847/0004-637X/820/2/93

astro-ph.EP

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

We characterize the eccentricity distribution of a sample of ~50 short-period planet candidates using transit and occultation measurements from NASA's Kepler Mission. First, we evaluate the sensitivity of our hierarchical Bayesian modeling and test its robustness to model misspecification using simulated data. When analyzing actual data assuming a Rayleigh distribution for eccentricity, we find that the posterior mode for the dispersion parameter is $\sigma=0.081 \pm^{0.014}_{0.003}$. We find that a two-component Gaussian mixture model for $e \cos \omega$ and $e \sin \omega$ provides a better model than either a Rayleigh or Beta distribution. Based on our favored model, we find that $\sim90\%$ of planet candidates in our sample come from a population with an eccentricity distribution characterized by a small dispersion ($\sim0.01$), and $\sim10\%$ come from a population with a larger dispersion ($\sim0.22$). Finally, we investigate how the eccentricity distribution correlates with selected planet and host star parameters. We find evidence that suggests systems around higher metallicity stars and planet candidates with smaller radii come from a more complex eccentricity distribution.

[{'version': 'v1', 'created': 'Mon, 9 Nov 2015 21:00:02 GMT'}]

2016-04-06

[array(['Shabram', 'Megan', ''], dtype=object) array(['Demory', 'Brice-Olivier', ''], dtype=object) array(['Cisewski', 'Jessi', ''], dtype=object) array(['Ford', 'Eric B.', ''], dtype=object) array(['Rogers', 'Leslie', ''], dtype=object)]

2105.10314

Jean-Philip Piquemal

Christophe Gourlaouen and Jean-Philip Piquemal

On the Quantum Chemical Nature of Lead(II) "Lone Pair"

Molecules, 2022, 27(1), 27

10.3390/molecules27010027

physics.chem-ph

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

We discuss the quantum chemical nature of the Lead(II) valence basins, sometime called the Lead "lone pair". Using various chemical interpretation tools such as the molecular orbital analysis, Natural Bond Orbitals (NBO), Natural Population Analysis (NPA) and Electron Localization Function (ELF) topological analysis, we study a variety of Lead(II) complexes. A careful analysis of the results show that the optimal structures of the lead complexes are only govern by the 6s and 6p subshells whereas no involvement of the 5d orbitals is found. Similarly, we do not find any significant contribution of the 6d. Therefore, the Pb(II) complexation with its ligand can be explained through the interaction of the 6s2 electrons and the accepting 6p orbitals. We detail the potential structural and dynamical consequences of such electronic structure organization of the Pb (II) valence domain.

[{'version': 'v1', 'created': 'Fri, 21 May 2021 12:39:31 GMT'} {'version': 'v2', 'created': 'Thu, 2 Dec 2021 10:47:33 GMT'} {'version': 'v3', 'created': 'Thu, 16 Dec 2021 11:02:21 GMT'}]

2021-12-23

[array(['Gourlaouen', 'Christophe', ''], dtype=object) array(['Piquemal', 'Jean-Philip', ''], dtype=object)]

2107.06736

Simone Dovetta

Simone Dovetta, Elio Marconi, Laura V. Spinolo

New regularity results for scalar conservation laws, and applications to a source-destination model for traffic flows on networks

28 pages, 2 figures

math.AP

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

We focus on entropy admissible solutions of scalar conservation laws in one space dimension and establish new regularity results with respect to time. First, we assume that the flux function $f$ is strictly convex and show that, for every $ x \in \mathbb{R}$, the total variation of the composite function $f \circ u(\cdot, x)$ is controlled by the total variation of the initial datum. Next, we assume that $f$ is monotone and, under no convexity assumption, we show that, for every $x$, the total variation of the left and right trace $u(\cdot, x^\pm)$ is controlled by the total variation of the initial datum. We also exhibit a counter-example showing that in the first result the total variation bound does not extend to the function $u$, or equivalently that in the second result we cannot drop the monotonicity assumption. We then discuss applications to a source-destination model for traffic flows on road networks. We introduce a new approach, based on the analysis of transport equations with irregular coefficients, and, under the assumption that the network only contains so-called T-junctions, we establish existence and uniqueness results for merely bounded data in the class of solutions where the traffic is not congested. Our assumptions on the network and the traffic congestion are basically necessary to obtain well-posedness in view of a counter-example due to Bressan and Yu. We also establish stability and propagation of $BV$ regularity, and this is again interesting in view of recent counter-examples.

[{'version': 'v1', 'created': 'Wed, 14 Jul 2021 14:28:56 GMT'}]

2021-07-15

[array(['Dovetta', 'Simone', ''], dtype=object) array(['Marconi', 'Elio', ''], dtype=object) array(['Spinolo', 'Laura V.', ''], dtype=object)]

hep-ph/0408327

Wei Zhu

Wei Zhu, Zhenqi Shen, Jifeng Yang and Jianhong Ruan

A unity of QCD evolution dynamics at small $x$ region

43 pages, 21 figures, profoundly revised

hep-ph

The DGLAP, BFKL, modified DGLAP and modified BFKL equations are constructed in a unified partonic framework. The antishadowing effect in the recombination process is emphasized, which leads to two different small $x$ behaviors of gluon distribution. In the meantime, the BFKL equation and modified DGLAP equation are viewed as the corrections of the initial gluon correlations to the evolution dynamics at twist-2 and twist-4, respectively. A partonic explanation of Regge theory for the BFKL dynamics and the relation of the BFKL dynamics with the helicity configuration of the initial gluons are presented.

[{'version': 'v1', 'created': 'Mon, 30 Aug 2004 01:54:09 GMT'} {'version': 'v2', 'created': 'Sun, 1 Jan 2006 07:13:14 GMT'}]

2007-05-23

[array(['Zhu', 'Wei', ''], dtype=object) array(['Shen', 'Zhenqi', ''], dtype=object) array(['Yang', 'Jifeng', ''], dtype=object) array(['Ruan', 'Jianhong', ''], dtype=object)]

astro-ph/0010174

Sandy Leggett

S. K. Leggett, F. Allard, T. R. Geballe, P. H. Hauschildt, A. Schweitzer

Infrared Spectra and Spectral Energy Distributions of Late-M- and L-Dwarfs

31 pages incl. 5 Tables and 12 Figures, accepted by ApJ for Feb 2001 issue

10.1086/319020

astro-ph

We have obtained 1.0-2.5um spectra at R~600 of 14 disk dwarfs with spectral types M6 to L7. For four of the dwarfs we have also obtained infrared spectra at R~3000 in narrow intervals. In addition, we present new L' photometry for four of the dwarfs in the sample, which allows improved determinations of their bolometric luminosities. We resolve the L-dwarf Denis-P J 0205-1159 into an identical pair of objects separated by 0.35". The spectra, with the published energy distribution for one other dwarf, are compared to synthetic spectra generated by upgraded model atmospheres. Good matches are found for 2200> Teff K>1900 (spectral types around M9 to L3), but discrepancies exist at Teff> 2300 K (M8) and for Teff<1800 K (L4-L7). At the higher temperatures the mismatches are due to incompleteness in the water vapor linelist. At the lower temperatures the disagreement is probably due to our treatment of dust: we assume a photospheric distribution in equilibrium with the gas phase. We derive effective temperatures for the sample from the comparison with synthetic spectra and also by comparing our observed total intrinsic luminosities to structural model calculations (which are mostly independent of the atmosphere but are dependent on the unknown masses and ages of the targets). The two derivations agree to ~200 K except for the faintest object in the sample where the discrepancy is larger. Agreement with other temperature determinations is also ~200 K, except for the L7 dwarf.

[{'version': 'v1', 'created': 'Tue, 10 Oct 2000 01:25:16 GMT'}]

2009-10-31

[array(['Leggett', 'S. K.', ''], dtype=object) array(['Allard', 'F.', ''], dtype=object) array(['Geballe', 'T. R.', ''], dtype=object) array(['Hauschildt', 'P. H.', ''], dtype=object) array(['Schweitzer', 'A.', ''], dtype=object)]

1712.08820

Tomohiro Nakama

Tomohiro Nakama, Teruaki Suyama, Kazunori Kohri and Nagisa Hiroshima

Constraints on small-scale primordial power by annihilation signals from extragalactic dark matter minihalos

11 pages, 7 figures

Phys. Rev. D 97, 023539 (2018)

10.1103/PhysRevD.97.023539

KEK-Cosmo-219, KEK-TH-2026

astro-ph.CO gr-qc

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

We revisit constraints on small-scale primordial power from annihilation signals from dark matter minihalos. Using gamma rays and neutrinos from extragalactic minihalos and assuming the delta-function primordial spectrum, we show the dependence of the constraints on annihilation modes, the mass of dark matter, and the annihilation cross section. We report both conservative constraints by assuming minihalos are fully destructed when becoming part of halos originating from the standard almost-scale invariant primordial spectrum, and optimistic constraints by neglecting destruction.

[{'version': 'v1', 'created': 'Sat, 23 Dec 2017 18:47:35 GMT'}]

2018-02-07

[array(['Nakama', 'Tomohiro', ''], dtype=object) array(['Suyama', 'Teruaki', ''], dtype=object) array(['Kohri', 'Kazunori', ''], dtype=object) array(['Hiroshima', 'Nagisa', ''], dtype=object)]

2012.09812

Dhruv Shah

Dhruv Shah, Benjamin Eysenbach, Gregory Kahn, Nicholas Rhinehart, Sergey Levine

ViNG: Learning Open-World Navigation with Visual Goals

Presented at International Conference on Robotics and Automation (ICRA) 2021

10.1109/ICRA48506.2021.9561936

cs.RO cs.AI cs.LG

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

We propose a learning-based navigation system for reaching visually indicated goals and demonstrate this system on a real mobile robot platform. Learning provides an appealing alternative to conventional methods for robotic navigation: instead of reasoning about environments in terms of geometry and maps, learning can enable a robot to learn about navigational affordances, understand what types of obstacles are traversable (e.g., tall grass) or not (e.g., walls), and generalize over patterns in the environment. However, unlike conventional planning algorithms, it is harder to change the goal for a learned policy during deployment. We propose a method for learning to navigate towards a goal image of the desired destination. By combining a learned policy with a topological graph constructed out of previously observed data, our system can determine how to reach this visually indicated goal even in the presence of variable appearance and lighting. Three key insights, waypoint proposal, graph pruning and negative mining, enable our method to learn to navigate in real-world environments using only offline data, a setting where prior methods struggle. We instantiate our method on a real outdoor ground robot and show that our system, which we call ViNG, outperforms previously-proposed methods for goal-conditioned reinforcement learning, including other methods that incorporate reinforcement learning and search. We also study how \sysName generalizes to unseen environments and evaluate its ability to adapt to such an environment with growing experience. Finally, we demonstrate ViNG on a number of real-world applications, such as last-mile delivery and warehouse inspection. We encourage the reader to visit the project website for videos of our experiments and demonstrations sites.google.com/view/ving-robot.

[{'version': 'v1', 'created': 'Thu, 17 Dec 2020 18:22:32 GMT'} {'version': 'v2', 'created': 'Fri, 26 Mar 2021 11:12:28 GMT'}]

2022-10-11

[array(['Shah', 'Dhruv', ''], dtype=object) array(['Eysenbach', 'Benjamin', ''], dtype=object) array(['Kahn', 'Gregory', ''], dtype=object) array(['Rhinehart', 'Nicholas', ''], dtype=object) array(['Levine', 'Sergey', ''], dtype=object)]

2304.07130

S{\l}awomir Dadas

S{\l}awomir Dadas

OPI at SemEval 2023 Task 9: A Simple But Effective Approach to Multilingual Tweet Intimacy Analysis

cs.CL

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

This paper describes our submission to the SemEval 2023 multilingual tweet intimacy analysis shared task. The goal of the task was to assess the level of intimacy of Twitter posts in ten languages. The proposed approach consists of several steps. First, we perform in-domain pre-training to create a language model adapted to Twitter data. In the next step, we train an ensemble of regression models to expand the training set with pseudo-labeled examples. The extended dataset is used to train the final solution. Our method was ranked first in five out of ten language subtasks, obtaining the highest average score across all languages.

[{'version': 'v1', 'created': 'Fri, 14 Apr 2023 13:49:28 GMT'}]

2023-04-17

[array(['Dadas', 'Sławomir', ''], dtype=object)]

0711.3688

Jean-Andre Marti

Jean-Andr\'e Marti (GTSI)

Regularity, Local and Microlocal Analysis in Theories of Generalized Functions

math.FA

We introduce a general context involving a presheaf A and a subpresheaf B of A. We show that all previously considered cases of local analysis of generalized functions (defined from duality or algebraic techniques) can be interpretated as the B-local analysis of sections of A. But the microlocal analysis of the sections of sheaves or presheaves under consideration is dissociated into a "frequential microlocal analysis " and into a "microlocal asymptotic analysis". The frequential microlocal analysis based on the Fourier transform leads to the study of propagation of singularities under only linear (including pseudodifferential) operators in the theories described here, but has been extended to some non linear cases in classical theories involving Sobolev techniques. The microlocal asymptotic analysis can inherit from the algebraic structure of B some good properties with respect to nonlinear operations.

[{'version': 'v1', 'created': 'Fri, 23 Nov 2007 09:39:18 GMT'}]

2007-11-26

[array(['Marti', 'Jean-André', '', 'GTSI'], dtype=object)]

2107.00529

Tommaso Benciolini

Tommaso Benciolini, Tim Br\"udigam, Marion Leibold

Multistage Stochastic Model Predictive Control for Urban Automated Driving

This work has been accepted to the IEEE 2021 International Conference on Intelligent Transportation Systems. The published version may be found at https://doi.org/10.1109/ITSC48978.2021.9564572

10.1109/ITSC48978.2021.9564572

eess.SY cs.SY

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

Trajectory planning in urban automated driving is challenging because of the high uncertainty resulting from the unknown future motion of other traffic participants. Robust approaches guarantee safety, but tend to result in overly conservative motion planning. Hence, we propose to use Stochastic Model Predictive Control for vehicle control in urban driving, allowing to efficiently plan the vehicle trajectory, while maintaining the risk probability sufficiently low. For motion optimization, we propose to use a two-stage hierarchical structure that plans the trajectory and the maneuver separately. A high-level layer takes advantage of a long prediction horizon and of an abstract model to plan the optimal maneuver, and a lower level is in charge of executing the selected maneuver by properly planning the vehicle's trajectory. Numerical simulations are included, showing the potential of our proposal.

[{'version': 'v1', 'created': 'Thu, 1 Jul 2021 15:16:42 GMT'} {'version': 'v2', 'created': 'Sat, 27 Nov 2021 09:13:07 GMT'}]

2021-11-30

[array(['Benciolini', 'Tommaso', ''], dtype=object) array(['Brüdigam', 'Tim', ''], dtype=object) array(['Leibold', 'Marion', ''], dtype=object)]

1202.0792

Andreas Menzel

Andreas M. Menzel

Collective motion of binary self-propelled particle mixtures

16 pages, 10 figures

Phys. Rev. E 85, 021912 (2012)

10.1103/PhysRevE.85.021912

cond-mat.soft cond-mat.stat-mech

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

In this study, we investigate the phenomenon of collective motion in binary mixtures of self-propelled particles. We consider two particle species, each of which consisting of pointlike objects that propel with a velocity of constant magnitude. Within each species, the particles try to achieve polar alignment of their velocity vectors, whereas we analyze the cases of preferred polar, antiparallel, as well as perpendicular alignment between particles of different species. Our focus is on the effect that the interplay between the two species has on the threshold densities for the onset of collective motion and on the nature of the solutions above onset. For this purpose, we start from suitable Langevin equations in the particle picture, from which we derive mean field equations of the Fokker-Planck type and finally macroscopic continuum field equations. We perform particle simulations of the Langevin equations, linear stability analyses of the Fokker-Planck and macroscopic continuum equations, and we numerically solve the Fokker-Planck equations. Both, spatially homogeneous and inhomogeneous solutions are investigated, where the latter correspond to stripe-like flocks of collectively moving particles. In general, the interaction between the two species reduces the threshold density for the onset of collective motion of each species. However, this interaction also reduces the spatial organization in the stripe-like flocks. The most interesting behavior is found for the case of preferred perpendicular alignment between different species. There, a competition between polar and truly nematic orientational ordering of the velocity vectors takes place within each particle species. Finally, depending on the alignment rule for particles of different species and within certain ranges of particle densities, identical and inverted spatial density profiles can be found for the two particle species.

[{'version': 'v1', 'created': 'Fri, 3 Feb 2012 18:17:56 GMT'}]

2013-11-20

[array(['Menzel', 'Andreas M.', ''], dtype=object)]

1610.08472

Vladimir Kirilin

S. Giombi, V. Gurucharan, V. Kirilin, S. Prakash, E. Skvortsov

On the Higher-Spin Spectrum in Large N Chern-Simons Vector Models

52 pages, 7 figures. v3: Minor corrections

10.1007/JHEP01(2017)058

PUPT-2512, LMU-ASC 52/16

hep-th

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

Chern-Simons gauge theories coupled to massless fundamental scalars or fermions define interesting non-supersymmetric 3d CFTs that possess approximate higher-spin symmetries at large N. In this paper, we compute the scaling dimensions of the higher-spin operators in these models, to leading order in the 1/N expansion and exactly in the 't Hooft coupling. We obtain these results in two independent ways: by using conformal symmetry and the classical equations of motion to fix the structure of the current non-conservation, and by a direct Feynman diagram calculation. The full dependence on the 't Hooft coupling can be restored by using results that follow from the weakly broken higher-spin symmetry. This analysis also allows us to obtain some explicit results for the non-conserved, parity-breaking structures that appear in planar three-point functions of the higher-spin operators. At large spin, we find that the anomalous dimensions grow logarithmically with the spin, in agreement with general expectations. This logarithmic behavior disappears in the strong coupling limit, where the anomalous dimensions turn into those of the critical O(N) or Gross-Neveu models, in agreement with the conjectured 3d bosonization duality.

[{'version': 'v1', 'created': 'Wed, 26 Oct 2016 19:23:25 GMT'} {'version': 'v2', 'created': 'Fri, 18 Nov 2016 13:54:36 GMT'} {'version': 'v3', 'created': 'Tue, 19 Sep 2017 19:02:40 GMT'}]

2017-09-21

[array(['Giombi', 'S.', ''], dtype=object) array(['Gurucharan', 'V.', ''], dtype=object) array(['Kirilin', 'V.', ''], dtype=object) array(['Prakash', 'S.', ''], dtype=object) array(['Skvortsov', 'E.', ''], dtype=object)]

1512.05676

Dinko Atanasov Da

D. Atanasov, P. Ascher, K. Blaum, R. B. Cakirli, T. E. Cocolios, S. George, F. Herfurth, D. Kisler, M. Kowalska, S. Kreim, Yu. A. Litvinov, D. Lunney, V. Manea, D. Neidherr, M. Rosenbusch, L. Schweikhard, A. Welker, F. Wienholtz, R. N. Wolf, K. Zuber

Precision Mass Measurements of 129-131Cd and Their Impact on Stellar Nucleosynthesis via the Rapid Neutron Capture Process

Phys. Rev. Lett. 115, 232501 (2015)

10.1103/PhysRevLett.115.232501

nucl-ex

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

Masses adjacent to the classical waiting-point nuclide 130Cd have been measured by using the Penning- trap spectrometer ISOLTRAP at ISOLDE/CERN. We find a significant deviation of over 400 keV from earlier values evaluated by using nuclear beta-decay data. The new measurements show the reduction of the N = 82 shell gap below the doubly magic 132Sn. The nucleosynthesis associated with the ejected wind from type-II supernovae as well as from compact object binary mergers is studied, by using state-of-the-art hydrodynamic simulations. We find a consistent and direct impact of the newly measured masses on the calculated abundances in the A = 128 - 132 region and a reduction of the uncertainties from the precision mass input data.

[{'version': 'v1', 'created': 'Thu, 17 Dec 2015 17:20:59 GMT'}]

2015-12-18

[array(['Atanasov', 'D.', ''], dtype=object) array(['Ascher', 'P.', ''], dtype=object) array(['Blaum', 'K.', ''], dtype=object) array(['Cakirli', 'R. B.', ''], dtype=object) array(['Cocolios', 'T. E.', ''], dtype=object) array(['George', 'S.', ''], dtype=object) array(['Herfurth', 'F.', ''], dtype=object) array(['Kisler', 'D.', ''], dtype=object) array(['Kowalska', 'M.', ''], dtype=object) array(['Kreim', 'S.', ''], dtype=object) array(['Litvinov', 'Yu. A.', ''], dtype=object) array(['Lunney', 'D.', ''], dtype=object) array(['Manea', 'V.', ''], dtype=object) array(['Neidherr', 'D.', ''], dtype=object) array(['Rosenbusch', 'M.', ''], dtype=object) array(['Schweikhard', 'L.', ''], dtype=object) array(['Welker', 'A.', ''], dtype=object) array(['Wienholtz', 'F.', ''], dtype=object) array(['Wolf', 'R. N.', ''], dtype=object) array(['Zuber', 'K.', ''], dtype=object)]

math/0502464

Ser-Peow Tan

Ser Peow Tan, Yan Loi Wong, Ying Zhang

Generalized Markoff Maps and McShane's Identity

49 pages, 9 figures

Advances in Mathematics 217:2 (2008) 761-813

10.1016/j.aim.2007.09.004

math.GT math.DG

We study general representations of the free group on two generators into $SL(2,C)$, and the connection with generalized Markoff maps, following Bowditch. We show that Bowditch's Q-conditions for generalized Markoff maps are sufficient for the generalized McShane identity to hold for the corresponding representations and that the subset of representations satisfying these conditions is the largest open subset in the relative character variety on which the mapping class group acts properly discontinuously. Moreover we generalize Bowditch's results on variations of McShane's identity for complete, finite volume hyperbolic 3-manifolds which fiber over the circle, with the fiber a punctured-torus, to identities for incomplete hyperbolic structures on such manifolds, hence obtaining identities for closed hyperbolic 3-manifolds which are obtained by doing hyperbolic Dehn surgery on such manifolds.

[{'version': 'v1', 'created': 'Tue, 22 Feb 2005 19:07:22 GMT'}]

2007-11-21

[array(['Tan', 'Ser Peow', ''], dtype=object) array(['Wong', 'Yan Loi', ''], dtype=object) array(['Zhang', 'Ying', ''], dtype=object)]

1203.0141

Xiaosong Chen

Maoxin Liu, Jingfang Fan, Liangsheng Li, and Xiaosong Chen

Continuous Percolation Phase Transitions of Two-dimensional Lattice Networks under a Generalized Achlioptas Process

7 pages, 14 figures, accepted for publication in Eur. Phys. J. B

10.1140/epjb/e2012-20872-1

cond-mat.stat-mech

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

The percolation phase transitions of two-dimensional lattice networks under a generalized Achlioptas process (GAP) are investigated. During the GAP, two edges are chosen randomly from the lattice and the edge with minimum product of the two connecting cluster sizes is taken as the next occupied bond with a probability $p$. At $p=0.5$, the GAP becomes the random growth model and leads to the minority product rule at $p=1$. Using the finite-size scaling analysis, we find that the percolation phase transitions of these systems with $0.5 \le p \le 1$ are always continuous and their critical exponents depend on $p$. Therefore, the universality class of the critical phenomena in two-dimensional lattice networks under the GAP is related to the probability parameter $p$ in addition.

[{'version': 'v1', 'created': 'Thu, 1 Mar 2012 10:50:20 GMT'}]

2012-03-02

[array(['Liu', 'Maoxin', ''], dtype=object) array(['Fan', 'Jingfang', ''], dtype=object) array(['Li', 'Liangsheng', ''], dtype=object) array(['Chen', 'Xiaosong', ''], dtype=object)]

cond-mat/0510722

Ilya Finkler

Ilya Finkler, Bertrand I. Halperin (Harvard), Assa Auerbach (Technion), Amir Yacoby (Weizmann)

Domain Patterns in the Microwave-Induced Zero-Resistance State

19 pages, 5 figures; submitted to a special issue of Journal of Statistical Physics, in honor of P. C. Hohenberg and J. S. Langer

10.1007/s10955-006-9037-7

cond-mat.mes-hall

It has been proposed that the microwave-induced ``zero-resistance'' phenomenon, observed in a GaAs two-dimensional electron system at low temperatures in moderate magnetic fields, results from a state with multiple domains, in which a large local electric field $\bE(\br)$ is oriented in different directions. We explore here the questions of what may determine the domain arrangement in a given sample, what do the domains look like in representative cases, and what may be the consequences of domain-wall localization on the macroscopic dc conductance. We consider both effects of sample boundaries and effects of disorder, in a simple model, which has a constant Hall conductivity, and is characterized by a Lyapunov functional.

[{'version': 'v1', 'created': 'Thu, 27 Oct 2005 05:19:39 GMT'}]

2015-06-25

[array(['Finkler', 'Ilya', '', 'Harvard'], dtype=object) array(['Halperin', 'Bertrand I.', '', 'Harvard'], dtype=object) array(['Auerbach', 'Assa', '', 'Technion'], dtype=object) array(['Yacoby', 'Amir', '', 'Weizmann'], dtype=object)]

1805.00556

Stefano Markidis Prof.

Sai Narasimhamurthy, Nikita Danilov, Sining Wu, Ganesan Umanesan, Stefano Markidis, Sergio Rivas-Gomez, Ivy Bo Peng, Erwin Laure, Dirk Pleiter, Shaun de Witt

SAGE: Percipient Storage for Exascale Data Centric Computing

Parallel Computing, 23 March 2018

10.1016/j.parco.2018.03.002

cs.DC

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

We aim to implement a Big Data/Extreme Computing (BDEC) capable system infrastructure as we head towards the era of Exascale computing - termed SAGE (Percipient StorAGe for Exascale Data Centric Computing). The SAGE system will be capable of storing and processing immense volumes of data at the Exascale regime, and provide the capability for Exascale class applications to use such a storage infrastructure. SAGE addresses the increasing overlaps between Big Data Analysis and HPC in an era of next-generation data centric computing that has developed due to the proliferation of massive data sources, such as large, dispersed scientific instruments and sensors, whose data needs to be processed, analyzed and integrated into simulations to derive scientific and innovative insights. Indeed, Exascale I/O, as a problem that has not been sufficiently dealt with for simulation codes, is appropriately addressed by the SAGE platform. The objective of this paper is to discuss the software architecture of the SAGE system and look at early results we have obtained employing some of its key methodologies, as the system continues to evolve.

[{'version': 'v1', 'created': 'Tue, 1 May 2018 21:20:31 GMT'}]

2018-05-03

[array(['Narasimhamurthy', 'Sai', ''], dtype=object) array(['Danilov', 'Nikita', ''], dtype=object) array(['Wu', 'Sining', ''], dtype=object) array(['Umanesan', 'Ganesan', ''], dtype=object) array(['Markidis', 'Stefano', ''], dtype=object) array(['Rivas-Gomez', 'Sergio', ''], dtype=object) array(['Peng', 'Ivy Bo', ''], dtype=object) array(['Laure', 'Erwin', ''], dtype=object) array(['Pleiter', 'Dirk', ''], dtype=object) array(['de Witt', 'Shaun', ''], dtype=object)]

2204.03689

Erin Beckman

Louigi Addario-Berry, Erin Beckman, Jessica Lin

Symmetric cooperative motion in one dimension

33 pages, 0 figures

math.PR cs.NA math.AP math.NA

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

We explore the relationship between recursive distributional equations and convergence results for finite difference schemes of parabolic partial differential equations (PDEs). We focus on a family of random processes called symmetric cooperative motions, which generalize the symmetric simple random walk and the symmetric hipster random walk introduced in [Addario-Berry, Cairns, Devroye, Kerriou and Mitchell, arXiv:1909.07367]. We obtain a distributional convergence result for symmetric cooperative motions and, along the way, obtain a novel proof of the Bernoulli central limit theorem. In addition, we prove a PDE result relating distributional solutions and viscosity solutions of the porous medium equation and the parabolic $p$-Laplace equation, respectively, in one dimension.

[{'version': 'v1', 'created': 'Thu, 7 Apr 2022 18:41:33 GMT'}]

2022-04-11

[array(['Addario-Berry', 'Louigi', ''], dtype=object) array(['Beckman', 'Erin', ''], dtype=object) array(['Lin', 'Jessica', ''], dtype=object)]

hep-lat/9709125

Martin Luescher

S. Capitani, M. Guagnelli, M. Luescher, S. Sint, R. Sommer, P. Weisz and H. Wittig

Non-perturbative quark mass renormalization

Talk given at LATTICE '97, 6 pages, Latex source, 7 eps figures, needs epsfig

Nucl.Phys.Proc.Suppl. 63 (1998) 153-158

10.1016/S0920-5632(97)00707-X

DESY 97-188

hep-lat

We show that the renormalization factor relating the renormalization group invariant quark masses to the bare quark masses computed in lattice QCD can be determined non-perturbatively. The calculation is based on an extension of a finite-size technique previously employed to compute the running coupling in quenched QCD. As a by-product we obtain the $\Lambda$--parameter in this theory with completely controlled errors.

[{'version': 'v1', 'created': 'Fri, 26 Sep 1997 14:54:35 GMT'}]

2009-10-30

[array(['Capitani', 'S.', ''], dtype=object) array(['Guagnelli', 'M.', ''], dtype=object) array(['Luescher', 'M.', ''], dtype=object) array(['Sint', 'S.', ''], dtype=object) array(['Sommer', 'R.', ''], dtype=object) array(['Weisz', 'P.', ''], dtype=object) array(['Wittig', 'H.', ''], dtype=object)]

1701.07100

Sebastian Streichan

Sebastian J Streichan and Matthew F Lefebvre and Nicholas Noll and Eric F Wieschaus and Boris I Shraiman

Quantification of myosin distribution predicts global morphogenetic flow in the fly embryo

15 total pages, with 9 total figures (7 pages main text with 4 figures and 8 pages SI text with 5 SI figures)

q-bio.TO q-bio.CB q-bio.QM

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

During embryogenesis tissue layers continuously rearrange and fold into specific shapes. Developmental biology identified patterns of gene expression and cytoskeletal regulation underlying local tissue dynamics, but how actions of multiple domains of distinct cell types coordinate to remodel tissues at the organ scale remains unclear. We use in toto light-sheet microscopy, automated image analysis, and physical modeling to quantitatively investigate the link between kinetics of global tissue transformations and force generation patterns during Drosophila gastrulation. We find embryo-scale shape changes are represented by a temporal sequence of three simple flow field configurations. Each phase is accompanied by a characteristic spatial myosin distribution, quantified in terms of a coarse-grained 'myosin tensor' that captures both concentration and anisotropy. Our model assumes tissue flow is driven by stress proportional to the myosin tensor, and is effectively visco-elastic with two parameters that control 'irrotational' and 'divergence-less' components of the flow. With just three global parameters, this model achieves up to 90% agreement between predicted and measured flow. The analysis uncovers importance of a) spatial modulation of myosin distribution and b) long-range spreading of its effect due to mechanical interaction of cells. In particular, we find germband extension phase is associated with the onset of effective areal incompressibility of the epithelium, which makes the relation of flow and myosin forcing strongly non-local. Our analysis also revealed a new function for basal myosin in generating a dorsally directed flow and, combined with mutant analysis, identified an unconventional control mechanism through twist dependent reduction of basal myosin levels on the ventral side. We conclude that understanding morphogenetic flow requires a fundamentally global perspective.

[{'version': 'v1', 'created': 'Tue, 24 Jan 2017 22:56:37 GMT'}]

2017-01-26

[array(['Streichan', 'Sebastian J', ''], dtype=object) array(['Lefebvre', 'Matthew F', ''], dtype=object) array(['Noll', 'Nicholas', ''], dtype=object) array(['Wieschaus', 'Eric F', ''], dtype=object) array(['Shraiman', 'Boris I', ''], dtype=object)]

1704.07607

Denys Dutykh

Suelen Gasparin (LAMA, PUCPR), Julien Berger (LOCIE), Denys Dutykh (LAMA), Nathan Mendes (PUCPR)

Solving nonlinear diffusive problems in buildings by means of a Spectral Reduced-Order Model

42 pages, 22 figures, 2 tables, 51 references. Other author's papers can be downloaded at http://www.denys-dutykh.com/

Journal of Building Performance Simulation (2019), Vol. 12, Issue 1, pp. 17-36

10.1080/19401493.2018.1458905

physics.comp-ph cs.NA math.AP math.NA physics.class-ph

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

This paper proposes the use of a Spectral method to simulate diffusive moisture transfer through porous materials as a Reduced-Order Model (ROM). The Spectral approach is an a priori method assuming a separated representation of the solution. The method is compared with both classical Euler implicit and Crank-Nicolson schemes, considered as large original models. Their performance - in terms of accuracy, complexity reduction and CPU time reduction - are discussed for linear and nonlinear cases of moisture diffusive transfer through single and multi-layered one-dimensional domains, considering highly moisture-dependent properties. Results show that the Spectral reduced-order model approach enables to simulate accurately the field of interest. Furthermore, numerical gains become particularly interesting for nonlinear cases since the proposed method can drastically reduce the computer run time, by a factor of 100, when compared to the traditional Crank-Nicolson scheme for one-dimensional applications.

[{'version': 'v1', 'created': 'Tue, 25 Apr 2017 09:36:59 GMT'} {'version': 'v2', 'created': 'Tue, 17 Apr 2018 14:25:56 GMT'}]

2020-02-20

[array(['Gasparin', 'Suelen', '', 'LAMA, PUCPR'], dtype=object) array(['Berger', 'Julien', '', 'LOCIE'], dtype=object) array(['Dutykh', 'Denys', '', 'LAMA'], dtype=object) array(['Mendes', 'Nathan', '', 'PUCPR'], dtype=object)]

gr-qc/0612121

Michael Seifert

Michael D. Seifert and Robert M. Wald

A general variational principle for spherically symmetric perturbations in diffeomorphism covariant theories

13 pages; submitted to Phys. Rev. D. v2: changed formatting, added conclusion, corrected sign conventions

Phys.Rev.D75:084029,2007

10.1103/PhysRevD.75.084029

gr-qc

We present a general method for the analysis of the stability of static, spherically symmetric solutions to spherically symmetric perturbations in an arbitrary diffeomorphism covariant Lagrangian field theory. Our method involves fixing the gauge and solving the linearized gravitational field equations to eliminate the metric perturbation variable in terms of the matter variables. In a wide class of cases--which include f(R) gravity, the Einstein-aether theory of Jacobson and Mattingly, and Bekenstein's TeVeS theory--the remaining perturbation equations for the matter fields are second order in time. We show how the symplectic current arising from the original Lagrangian gives rise to a symmetric bilinear form on the variables of the reduced theory. If this bilinear form is positive definite, it provides an inner product that puts the equations of motion of the reduced theory into a self-adjoint form. A variational principle can then be written down immediately, from which stability can be tested readily. We illustrate our method in the case of Einstein's equation with perfect fluid matter, thereby re-deriving, in a systematic manner, Chandrasekhar's variational principle for radial oscillations of spherically symmetric stars. In a subsequent paper, we will apply our analysis to f(R) gravity, the Einstein-aether theory, and Bekenstein's TeVeS theory.

[{'version': 'v1', 'created': 'Tue, 19 Dec 2006 20:57:57 GMT'} {'version': 'v2', 'created': 'Fri, 9 Mar 2007 22:51:58 GMT'}]

2008-11-26

[array(['Seifert', 'Michael D.', ''], dtype=object) array(['Wald', 'Robert M.', ''], dtype=object)]

2208.05444

Heather Kulik

Chenru Duan, Aditya Nandy, Gianmarco Terrones, David W. Kastner, and Heather J. Kulik

Active Learning Exploration of Transition Metal Complexes to Discover Method-Insensitive and Synthetically Accessible Chromophores

physics.chem-ph cond-mat.mtrl-sci cs.LG q-bio.BM

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

Transition metal chromophores with earth-abundant transition metals are an important design target for their applications in lighting and non-toxic bioimaging, but their design is challenged by the scarcity of complexes that simultaneously have optimal target absorption energies in the visible region as well as well-defined ground states. Machine learning (ML) accelerated discovery could overcome such challenges by enabling screening of a larger space, but is limited by the fidelity of the data used in ML model training, which is typically from a single approximate density functional. To address this limitation, we search for consensus in predictions among 23 density functional approximations across multiple rungs of Jacobs ladder. To accelerate the discovery of complexes with absorption energies in the visible region while minimizing MR character, we use 2D efficient global optimization to sample candidate low-spin chromophores from multi-million complex spaces. Despite the scarcity (i.e., approx. 0.01\%) of potential chromophores in this large chemical space, we identify candidates with high likelihood (i.e., > 10\%) of computational validation as the ML models improve during active learning, representing a 1,000-fold acceleration in discovery. Absorption spectra of promising chromophores from time-dependent density functional theory verify that 2/3 of candidates have the desired excited state properties. The observation that constituent ligands from our leads have demonstrated interesting optical properties in the literature exemplifies the effectiveness of our construction of a realistic design space and active learning approach.

[{'version': 'v1', 'created': 'Wed, 10 Aug 2022 16:55:33 GMT'} {'version': 'v2', 'created': 'Thu, 15 Sep 2022 16:15:21 GMT'}]

2022-09-16

[array(['Duan', 'Chenru', ''], dtype=object) array(['Nandy', 'Aditya', ''], dtype=object) array(['Terrones', 'Gianmarco', ''], dtype=object) array(['Kastner', 'David W.', ''], dtype=object) array(['Kulik', 'Heather J.', ''], dtype=object)]

1705.02198

Geoff Boeing

Geoff Boeing

A Multi-Scale Analysis of 27,000 Urban Street Networks: Every US City, Town, Urbanized Area, and Zillow Neighborhood

Environment and Planning B: Urban Analytics and City Science, 2018

10.1177/2399808318784595

cs.SI physics.soc-ph

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

OpenStreetMap offers a valuable source of worldwide geospatial data useful to urban researchers. This study uses the OSMnx software to automatically download and analyze 27,000 US street networks from OpenStreetMap at metropolitan, municipal, and neighborhood scales - namely, every US city and town, census urbanized area, and Zillow-defined neighborhood. It presents empirical findings on US urban form and street network characteristics, emphasizing measures relevant to graph theory, transportation, urban design, and morphology such as structure, connectedness, density, centrality, and resilience. In the past, street network data acquisition and processing have been challenging and ad hoc. This study illustrates the use of OSMnx and OpenStreetMap to consistently conduct street network analysis with extremely large sample sizes, with clearly defined network definitions and extents for reproducibility, and using nonplanar, directed graphs. These street networks and measures data have been shared in a public repository for other researchers to use.

[{'version': 'v1', 'created': 'Wed, 29 Mar 2017 21:06:13 GMT'} {'version': 'v2', 'created': 'Wed, 14 Feb 2018 18:56:53 GMT'} {'version': 'v3', 'created': 'Tue, 5 Jun 2018 15:52:30 GMT'} {'version': 'v4', 'created': 'Thu, 2 Aug 2018 18:37:12 GMT'}]

2018-08-06

[array(['Boeing', 'Geoff', ''], dtype=object)]

1503.04606

Michal Kowal

E. Ruchowska, H. Mach, M. Kowal, J. Skalski, W. A. Plociennik, B. Fogelberg

Search for octupole correlations in $^{147}$Nd

Submitted to PRC

10.1103/PhysRevC.92.034328

nucl-th nucl-ex

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

Properties of excited states in $^{147}$Nd have been studied with multispectra and $\gamma \gamma$ coincidence measurements. Twenty-four new $\gamma$-lines and three new levels have been introduced into the level scheme of $^{147}$Nd. Lifetimes of eight excited levels in $^{147}$Nd, populated in the $\beta$ decay of $^{147}$Pr, have been measured using the advanced time-delayed $\beta\gamma\gamma$(t) method. Reduced transition probabilities have been determined for 30 $\gamma$-transitions in $^{147}$Nd. Potential energy surfaces on the ($\beta_{2}$,$\beta_{3}$) plane calculated for $^{147}$Nd using the Strutinsky method predict two single quasiparticle configurations with nonzero octupole deformation, with K=1/2 and K=5/2. We do not observe parity doublet bands with K=5/2. For pair of opposite parity bands that could form the K=1/2 parity doublet we were able only to determine lower limit of the dipole moment, $|D_0|\geq$0.02 e$\cdot fm$.

[{'version': 'v1', 'created': 'Mon, 16 Mar 2015 11:14:05 GMT'}]

2015-10-28

[array(['Ruchowska', 'E.', ''], dtype=object) array(['Mach', 'H.', ''], dtype=object) array(['Kowal', 'M.', ''], dtype=object) array(['Skalski', 'J.', ''], dtype=object) array(['Plociennik', 'W. A.', ''], dtype=object) array(['Fogelberg', 'B.', ''], dtype=object)]

hep-ph/0411026

Edmond Berger

Edmond L. Berger, Jianwei Qiu, and Yili Wang

Upsilon Transverse Momentum at Hadron Colliders

4 pages, 5 figures. Presented at the 2004 Meeting of the APS Division of Particles and Fields, University of California, Riverside, CA, Aug 26-31, 2004

Int.J.Mod.Phys.A20:3753-3755,2005

10.1142/S0217751X05027515

ANL-HEP-CP-04-110

hep-ph

We predict the shape of the transverse momentum p_T spectrum of Upsilon production. The distribution at low p_T is dominated by the region of small impact parameter b and may be computed reliably in perturbation theory. We resum to all orders in the strong coupling alpha_s the process-independent large logarithmic contributions that arise from initial-state gluon showers in the small p_T (< M_Upsilon) region. The cross section at large p_T is represented by the alpha_s^3 lowest-order non-vanishing perturbative contribution.

[{'version': 'v1', 'created': 'Mon, 1 Nov 2004 21:39:01 GMT'}]

2014-11-18

[array(['Berger', 'Edmond L.', ''], dtype=object) array(['Qiu', 'Jianwei', ''], dtype=object) array(['Wang', 'Yili', ''], dtype=object)]

astro-ph/0110660

Konishchev K. V.

E. V. Bugaev, M. G. Elbakidze and K. V. Konishchev

Baryon asymmetry of the Universe from evaporation of primordial black holes

5 pages (including 6 .eps files)

Phys.Atom.Nucl. 66 (2003) 476-480; Yad.Fiz. 66 (2003) 504-508

10.1134/1.1563709

astro-ph

The process of baryogenesis through the evaporation of black holes formed at the end of inflation phase is considered. The increase of black hole mass due to accretion from the surrounding radiation after the reheating is taken into account. It is shown that the influence of the accretion on the baryogenesis is important only in the case when the initial values of black hole mass are larger than $\sim 10^{4}{g}$. The behavior of calculated baryon asymmetry, as a function of model parameters, is studied.

[{'version': 'v1', 'created': 'Tue, 30 Oct 2001 16:59:37 GMT'} {'version': 'v2', 'created': 'Wed, 31 Oct 2001 14:26:09 GMT'} {'version': 'v3', 'created': 'Fri, 2 Nov 2001 13:00:00 GMT'}]

2015-06-24

[array(['Bugaev', 'E. V.', ''], dtype=object) array(['Elbakidze', 'M. G.', ''], dtype=object) array(['Konishchev', 'K. V.', ''], dtype=object)]

2109.10732

Gabriele Grillo

Elvise Berchio, Matteo Bonforte, Gabriele Grillo, Matteo Muratori

The Fractional Porous Medium Equation on noncompact Riemannian manifolds

math.AP math.DG math.FA

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

We study nonnegative solutions to the Fractional Porous Medium Equation on a suitable class of connected, noncompact Riemannian manifolds. We provide existence and smoothing estimates for solutions, in an appropriate weak (dual) sense, for data belonging either to the usual $L^1$ space or to a considerably larger weighted space determined in terms of the fractional Green function. The class of manifolds for which the results hold include both the Euclidean and the hyperbolic spaces and even in the Euclidean situation involve a class of data which is larger than previously known one.

[{'version': 'v1', 'created': 'Wed, 22 Sep 2021 13:38:40 GMT'}]

2021-09-23

[array(['Berchio', 'Elvise', ''], dtype=object) array(['Bonforte', 'Matteo', ''], dtype=object) array(['Grillo', 'Gabriele', ''], dtype=object) array(['Muratori', 'Matteo', ''], dtype=object)]

hep-th/9805190

Harald Skarke

M. Kreuzer and H. Skarke

Classification of Reflexive Polyhedra in Three Dimensions

19 pages, LaTeX2e

Adv.Theor.Math.Phys.2:847-864,1998

TUW-98-13, UTTG-07-98

hep-th math.AG

We present the last missing details of our algorithm for the classification of reflexive polyhedra in arbitrary dimensions. We also present the results of an application of this algorithm to the case of three dimensional reflexive polyhedra. We get 4319 such polyhedra that give rise to K3 surfaces embedded in toric varieties. 16 of these contain all others as subpolyhedra. The 4319 polyhedra form a single connected web if we define two polyhedra to be connected if one of them contains the other.

[{'version': 'v1', 'created': 'Wed, 27 May 1998 21:15:44 GMT'}]

2008-11-26

[array(['Kreuzer', 'M.', ''], dtype=object) array(['Skarke', 'H.', ''], dtype=object)]

1312.3465

James Osborn

H. W. Shepherd, J. Osborn, R. W. Wilson, T. Butterley, R. Avila, V. S. Dhillon and T. J. Morris

Stereo-SCIDAR: Optical turbulence profiling with high sensitivity using a modified SCIDAR instrument

11 pages, 11 figures, accepted by MNRAS 27/11/13

MNRAS, 437(4), 3568-3577, 2013

10.1093/mnras/stt2150

astro-ph.IM

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

The next generation of adaptive optics (AO) systems will require tomographic reconstruction techniques to map the optical refractive index fluctuations, generated by the atmospheric turbulence, along the line of sight to the astronomical target. These systems can be enhanced with data from an external atmospheric profiler. This is important for Extremely Large Telescope scale tomography. Here we propose a new instrument which utilises the generalised SCIntillation Detection And Ranging (SCIDAR) technique to allow high sensitivity vertical profiles of the atmospheric optical turbulence and wind velocity profile above astronomical observatories. The new approach, which we refer to as 'Stereo-SCIDAR', uses a stereoscopic system with the scintillation pattern from each star of a double-star target incident on a separate detector. Separating the pupil images for each star has several advantages including: increased magnitude difference tolerance for the target stars; negating the need for re-calibration due to the normalisation errors usually associated with SCIDAR; an increase of at least a factor of two in the signal-to-noise ratio of the cross-covariance function and hence the profile for equal magnitude target stars and up to a factor of 16 improvement for targets of 3 magnitudes difference; and easier real-time reconstruction of the wind-velocity profile. Theoretical response functions are calculated for the instrument, and the performance is investigated using a Monte-Carlo simulation. The technique is demonstrated using data recorded at the 2.5 m Nordic Optical Telescope and the 1.0 m Jacobus Kapteyn Telescope, both on La Palma.

[{'version': 'v1', 'created': 'Thu, 12 Dec 2013 12:38:02 GMT'}]

2014-01-07

[array(['Shepherd', 'H. W.', ''], dtype=object) array(['Osborn', 'J.', ''], dtype=object) array(['Wilson', 'R. W.', ''], dtype=object) array(['Butterley', 'T.', ''], dtype=object) array(['Avila', 'R.', ''], dtype=object) array(['Dhillon', 'V. S.', ''], dtype=object) array(['Morris', 'T. J.', ''], dtype=object)]

2204.08792

Yandong Ma

Kaiying Dou, Wenhui Du, Zhonglin He, Ying Dai, Baibiao Huang, and Yandong Ma

Antiferromagnetic skyrmion crystal in Janus monolayer CrSi2N2As2

cond-mat.mtrl-sci

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

Antiferromagnetic skyrmion crystal (AF-SkX), a regular array of antiferromagnetic skyrmions, is a fundamental phenomenon in the field of condensed-matter physics. So far, only very few proposals have been made to realize the AF-SkX, and most based on three-dimensional (3D) materials. Herein, using first-principles calculations and Monte-Carlo simulations, we report the identification of AF-SkX in two-dimensional lattice of Janus monolayer CrSi2N2As2. Arising from the broken inversion symmetry and strong spin-orbit coupling, large Dzyaloshinskii-Moriya interaction is obtained in Janus monolayer CrSi2N2As2. This, combined with the geometric frustration of its triangular lattice, gives rise to the skyrmion physics and long-sought AF-SkX in the presence of external magnetic field. More intriguingly, this system presents two different antiferromagnetic skyrmion phases, and such phenomenon is distinct from those reported in 3D systems. Furthermore, by contacting with Sc2CO2, the creation and annihilation of AF-SkX in Janus monolayer CrSi2N2As2 can be achieved through ferroelectricity. These findings greatly enrich the research on antiferromagnetic skyrmions.

[{'version': 'v1', 'created': 'Tue, 19 Apr 2022 10:29:05 GMT'}]

2022-04-20

[array(['Dou', 'Kaiying', ''], dtype=object) array(['Du', 'Wenhui', ''], dtype=object) array(['He', 'Zhonglin', ''], dtype=object) array(['Dai', 'Ying', ''], dtype=object) array(['Huang', 'Baibiao', ''], dtype=object) array(['Ma', 'Yandong', ''], dtype=object)]

0811.3314

Kenji Kamide

Kenji Kamide, Takashi Kimura, and Susumu Kurihara

Tomonaga-Luttinger Liquid Renormalized by a Single Impurity

4pages, 2 figures

10.1088/1742-6596/150/2/022031

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

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

Effects of a single impurity potential on bulk properties of a spinful Tomonaga-Luttinger (TL) liquid is studied. A boundary bosonization technique is developed to include the impurity potential of {\it arbitrary} strength $V$. Our new bosonization formula for fermion field $\psi$ smoothly connects the two existing expressions in the strong ($V = \infty$) and the weak ($V = 0$) impurity limits. With use of the formula, we found the TL parameters determined from the long-distance correlation functions are renormalized due to the partial transmission through the impurity potential.

[{'version': 'v1', 'created': 'Thu, 20 Nov 2008 11:29:43 GMT'}]

2009-11-13

[array(['Kamide', 'Kenji', ''], dtype=object) array(['Kimura', 'Takashi', ''], dtype=object) array(['Kurihara', 'Susumu', ''], dtype=object)]

1007.4878

Francois Louchet

Paul Duval, Francois Louchet, Jerome Weiss and Maurine Montagnat

On the role of long range internal stresses on grain nucleation during discontinuous recrystallization

7 pages, 3 figures

cond-mat.mtrl-sci

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

The essential role of long range elastic interactions in recrystallization is demonstrated using a simple analytical model: pileup rearrangements following absorption of leading dislocations by a dislocation-free embryo provides an additional driving force that results in a drastic decrease of both the nucleation critical radius and the saddle point energy. A very sharp transition is evidenced, at which the saddle point totally disappears and nucleation becomes spontaneous. This transition occurs for a well defined critical stress corresponding to both a critical density of geometrically necessary dislocations and a critical strain, without invoking any critical nucleus size that may be reached with the help of some dislocation microstructure instability. The present model is illustrated here by the case of polycrystalline ice, but may apply to other crystalline material with significant plastic anisotropy, as Zircaloy for instance.

[{'version': 'v1', 'created': 'Wed, 28 Jul 2010 07:09:47 GMT'}]

2010-07-29

[array(['Duval', 'Paul', ''], dtype=object) array(['Louchet', 'Francois', ''], dtype=object) array(['Weiss', 'Jerome', ''], dtype=object) array(['Montagnat', 'Maurine', ''], dtype=object)]

math/0608170

Tomasz Brzezinski

Tomasz Brzezinski

Flat connections and (co)modules

18 pages, LaTeX; significantly expanded with two new sections on connections in (bi)comodules

math.QA math.RA

The relationship between comodules of a coring and flat connections is reviewed. In particular we specialise to corings which are built on a tensor product of algebra and a coalgebra. Such corings are in one-to-one correspondence with entwining structures, and their comodules are entwined modules. These include Yetter-Drinfeld and anti-Yetter-Drinfeld modules and their generalisations, hence all the modules of interest to Hopf-cyclic cohomology. In this way the interpretation of the latter as modules with flat connections [A Kaygun and M Khalkhali, Hopf modules and noncommutative differential geometry, Lett. Math. Phys. 76 (2006), 77--91] is obtained as a corollary of a more general theory. We also introduce the notions of a connection in a comodule and of a bicomodule connection, and show how comodules with flat connections can be interpreted as modules of a C-ring. In this way all the above mentioned Hopf modules can be interpreted as comodules with flat connections.

[{'version': 'v1', 'created': 'Mon, 7 Aug 2006 17:40:10 GMT'} {'version': 'v2', 'created': 'Fri, 19 Jan 2007 13:18:38 GMT'}]

2007-05-23

[array(['Brzezinski', 'Tomasz', ''], dtype=object)]

1506.08201

Robin Mostardi

Robin E. Mostardi, Alice E. Shapley, Charles C. Steidel, Ryan F. Trainor, Naveen A. Reddy, Brian Siana

A High-Resolution Hubble Space Telescope Study of Apparent Lyman Continuum Leakers at $z\sim3$

31 pages, 5 tables, 19 figures. Accepted to ApJ. Version with full-resolution figures is available at: http://www.astro.ucla.edu/~aes/Mostardi_HST_LyC.pdf

10.1088/0004-637X/810/2/107

astro-ph.GA

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

We present $U_{336}V_{606}J_{125}H_{160}$ follow-up $HST$ observations of 16 $z\sim3$ candidate LyC emitters in the HS1549+1919 field. With these data, we obtain high spatial-resolution photometric redshifts of all sub-arcsecond components of the LyC candidates in order to eliminate foreground contamination and identify robust candidates for leaking LyC emission. Of the 16 candidates, we find one object with a robust LyC detection that is not due to foreground contamination. This object (MD5) resolves into two components; we refer to the LyC-emitting component as MD5b. MD5b has an observed 1500\AA\ to 900\AA\ flux-density ratio of $(F_{UV}/F_{LyC})_{obs}=4.0\pm2.0$, compatible with predictions from stellar population synthesis models. Assuming minimal IGM absorption, this ratio corresponds to a relative (absolute) escape fraction of $f_{esc,rel}^{MD5b}=75-100$% ($f_{esc,abs}^{MD5b}=14-19$%). The stellar population fit to MD5b indicates an age of $\lesssim50$Myr, which is in the youngest 10% of the $HST$ sample and the youngest third of typical $z\sim3$ Lyman break galaxies, and may be a contributing factor to its LyC detection. We obtain a revised, contamination-free estimate for the comoving specific ionizing emissivity at $z=2.85$, indicating (with large uncertainties) that star-forming galaxies provide roughly the same contribution as QSOs to the ionizing background at this redshift. Our results show that foreground contamination prevents ground-based LyC studies from obtaining a full understanding of LyC emission from $z\sim3$ star-forming galaxies. Future progress in direct LyC searches is contingent upon the elimination of foreground contaminants through high spatial-resolution observations, and upon acquisition of sufficiently deep LyC imaging to probe ionizing radiation in high-redshift galaxies.

[{'version': 'v1', 'created': 'Fri, 26 Jun 2015 20:00:30 GMT'} {'version': 'v2', 'created': 'Sat, 1 Aug 2015 18:15:35 GMT'}]

2015-09-16

[array(['Mostardi', 'Robin E.', ''], dtype=object) array(['Shapley', 'Alice E.', ''], dtype=object) array(['Steidel', 'Charles C.', ''], dtype=object) array(['Trainor', 'Ryan F.', ''], dtype=object) array(['Reddy', 'Naveen A.', ''], dtype=object) array(['Siana', 'Brian', ''], dtype=object)]

1111.6105

Bing Shen

Bing Shen, Huan Yang, Bin Zeng, Cong Ren, Xibin Xu and Hai-Hu Wen

Multiple Magnetization Peaks and New Type of Vortex Phase Transitions in Ba0.6K0.4Fe2As2

5 page, 5 figures

cond-mat.supr-con

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

Magnetization and its relaxation have been measured on Ba0.6K0.4Fe2As2 single crystals with Tc = 39 K. The magnetization hysteresis loops (MHLs) exhibit flux jumps in the low temperature region, and a second peak-effect in the intermediate temperature region, especially when the field sweeping rate is low. Interestingly a third magnetization peak can be easily observed on the MHLs in the high temperature region. Further analysis find that the first magnetization peak is very sharp, which is associated with the strong vortex pinning. However the first dip of the MHL corresponds to a moderate relaxation rate, then a second peak appears accompanied by a vanishing vortex motion. Finally a third magnetization peak emerges and the vortex motion becomes drastic beyond this threshold. The novel features accompanying the second magnetization peak suggest a new type of vortex phase transition.

[{'version': 'v1', 'created': 'Fri, 25 Nov 2011 12:40:15 GMT'} {'version': 'v2', 'created': 'Wed, 30 Nov 2011 12:08:12 GMT'}]

2011-12-01

[array(['Shen', 'Bing', ''], dtype=object) array(['Yang', 'Huan', ''], dtype=object) array(['Zeng', 'Bin', ''], dtype=object) array(['Ren', 'Cong', ''], dtype=object) array(['Xu', 'Xibin', ''], dtype=object) array(['Wen', 'Hai-Hu', ''], dtype=object)]

1107.2127

Jesse Johnson

Jesse Johnson

An upper bound on common stabilizations of Heegaard splittings

34 pages, 8 figures

math.GT

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

We show that for any two Heegaard splittings of genus $p$ and $q$ for the same closed 3-manifold, there is a common stabilization of genus at most 3/2 p + 2q - 1. One may compare this to recent examples of Heegaard splittings whose smallest common stabilizations have genus at least $p+q$ or $p + 1/2 q$ depending on the notion of equivalence.

[{'version': 'v1', 'created': 'Mon, 11 Jul 2011 20:04:49 GMT'}]

2011-07-13

[array(['Johnson', 'Jesse', ''], dtype=object)]

2004.08325

Frantisek Marko

Frantisek Marko

Symmetrizers for Schur superalgebras

math.RA math.CO math.RT

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

For the Schur superalgebra $S=S(m|n,r)$ over a ground field $K$ of characteristic zero, we define symmetrizers $T^{\lambda}[i:j]$ of the ordered pairs of tableaux $T_i, T_j$ of the shape $\lambda$ and show that the $K$-span $A_{\lambda,K}$ of all symmetrizers $T^{\lambda}[i:j]$ has a basis consisting of $T^{\lambda}[i:j]$ for $T_i,T_j$ semistandard. The $S$-superbimodule $A_{\lambda,K}$ is identified as %$\Delta(\lambda)^*\otimes_K \nabla(\lambda)$, where $\Delta(\lambda)^*$ is the dual of the standard supermodule %and $\nabla(\lambda)$ is the costandard supermodule of the highest weight $\lambda$. $D_{\lambda}\otimes_K D^o_{\lambda}$, where $D_\lambda$ and $D^o_\lambda$ are left and right irreducible $S$-supermodules of the highest weight $\lambda$. We define modified symmetrizers $T^{\lambda}\{i:j\}$ and show that their $\mathbb{Z}$-span form a $\mathbb{Z}$-form $A_{\lambda,\mathbb{Z}}$ of $A_{\lambda, \mathbb{Q}}$. We show that every modified symmetrizer $T^\lambda\{i:j\}$ is a $\mathbb{Z}$-linear combination of symmetrizers $T^\lambda\{i:j\}$ for $T_i, T_j$ semistandard. Using modular reduction to a field $K$ of characteristic $p>2$, we obtain that $A_{\lambda,K}$ has a basis consisting of modified symmetrizers $T^\lambda\{i:j\}$ for $T_i, T_j$ semistandard.

[{'version': 'v1', 'created': 'Fri, 17 Apr 2020 16:12:45 GMT'}]

2020-04-20

[array(['Marko', 'Frantisek', ''], dtype=object)]

1408.0476

Meera Parish

Andrea M. Fischer and Meera M. Parish

Quasi-two-dimensional Fermi gases at finite temperature

8 pages, 4 figures

Phys. Rev. B 90, 214503 (2014)

10.1103/PhysRevB.90.214503

cond-mat.quant-gas cond-mat.supr-con

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

We consider a Fermi gas with short-range attractive interactions that is confined along one direction by a tight harmonic potential. For this quasi-two-dimensional (quasi-2D) Fermi gas, we compute the pressure equation of state, radio frequency spectrum, and the superfluid critical temperature $T_c$ using a mean-field theory that accounts for all the energy levels of the harmonic confinement. Our calculation for $T_c$ provides a natural generalization of the Thouless criterion to the quasi-2D geometry, and it correctly reduces to the 3D expression derived from the local density approximation in the limit where the confinement frequency $\omega_z \to 0$. Furthermore, our results suggest that $T_c$ can be enhanced by relaxing the confinement and perturbing away from the 2D limit.

[{'version': 'v1', 'created': 'Sun, 3 Aug 2014 09:35:56 GMT'}]

2014-12-08

[array(['Fischer', 'Andrea M.', ''], dtype=object) array(['Parish', 'Meera M.', ''], dtype=object)]

cond-mat/9907002

Daphne O. Klemme

Steven M. Girvin (Indiana University)

The Quantum Hall Effect: Novel Excitations and Broken Symmetries

124 pages. Lectures delivered at Ecole d'Ete Les Houches, July 1998

Topological Aspects of Low Dimensional Systems, ed. A. Comtet, T. Jolicoeur, S. Ouvry, F. David (Springer-Verlag, Berlin and Les Editions de Physique, Les Ulis, 2000)

IUCM98-010

cond-mat.mes-hall

These pedagogical lecture notes present a general introduction to most aspects of the integer and fractional quantum Hall effects. This is followed by an extensive discussion of quantum Hall ferromagnetism, both for spins in single-layer systems and `pseudospins' in double-layer systems. The effective field theories describing various broken symmetry states and `skyrmion' and `meron' spin textures are derived and discussed in some detail. Pedagogical presentations on Berry phases and lowest Landau level projection are included in appendices.

[{'version': 'v1', 'created': 'Thu, 1 Jul 1999 21:14:59 GMT'}]

2007-05-23

[array(['Girvin', 'Steven M.', '', 'Indiana University'], dtype=object)]

0806.4452

Yong-Wan Kim

Yun Soo Myung, Yong-Wan Kim, Young-Jai Park

Thermodynamics of Gauss-Bonnet black holes revisited

22 pages, 8 figures, version to appear in EPJC

Eur.Phys.J.C58:337-346,2008

10.1140/epjc/s10052-008-0745-9

gr-qc

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

We investigate the Gauss-Bonnet black hole in five dimensional anti-de Sitter spacetimes (GBAdS). We analyze all thermodynamic quantities of the GBAdS, which is characterized by the Gauss-Bonnet coupling $c$ and mass $M$, comparing with those of the Born-Infeld-AdS (BIAdS), Reissner-Norstr\"om-AdS black holes (RNAdS), Schwarzschild-AdS (SAdS), and BTZ black holes. For $c<0$ we cannot obtain the black hole with positively definite thermodynamic quantities of mass, temperature, and entropy because the entropy does not satisfy the area-law. On the other hand, for $c>0$, we find the BIAdS-like black hole, showing that the coupling $c$ plays the role of pseudo-charge. Importantly, we could not obtain the SAdS in the limits of $c\to 0$, which means that the GBAdS is basically different from the SAdS. In addition, we clarify the connections between thermodynamic and dynamical stability. Finally, we also conjecture that if a black hole is big and thus globally stable, its quasinormal modes may take analytic expressions.

[{'version': 'v1', 'created': 'Fri, 27 Jun 2008 08:30:55 GMT'} {'version': 'v2', 'created': 'Wed, 2 Jul 2008 07:23:11 GMT'} {'version': 'v3', 'created': 'Sat, 27 Sep 2008 15:24:49 GMT'}]

2008-12-18

[array(['Myung', 'Yun Soo', ''], dtype=object) array(['Kim', 'Yong-Wan', ''], dtype=object) array(['Park', 'Young-Jai', ''], dtype=object)]

1910.03711

Bryan Brzycki

Bryan Brzycki, Andrew P. V. Siemion, Steve Croft, Daniel Czech, David DeBoer, Julia DeMarines, Jamie Drew, J. Emilio Enriquez, Vishal Gajjar, Nectaria Gizani, Howard Isaacson, Brian C. Lacki, Matt Lebofsky, David H. E. MacMahon, Imke de Pater, Daniel C. Price, Sofia Z. Sheikh, Claire Webb, S. Pete Worden

Breakthrough Listen Follow-up of the Random Transiter (EPIC 249706694/HD 139139) with the Green Bank Telescope

3 pages, 1 table. Accepted for publication in RNAAS

astro-ph.EP astro-ph.IM

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

The star EPIC 249706694 (HD 139139) was found to exhibit 28 transit-like events over an 87 day period during the Kepler mission's K2 Campaign 15 (Rappaport et al. 2019). These events did not fall into an identifiable pattern and could not be explained by a multitude of transit scenarios explored by the authors. We conduct follow-up observations at C-band frequencies with the Green Bank Telescope as part of the ongoing Breakthrough Listen search for technosignatures. We search for narrow band signals above a signal-to-noise threshold of 10 and with Doppler drift rates within +-5 Hz/s. We detect no evidence of technosignatures from EPIC 249706694 and derive an upper limit for the EIRP (Equivalent Isotropic Radiated Power) of putative transmissions to be 10 TW.

[{'version': 'v1', 'created': 'Tue, 8 Oct 2019 22:57:00 GMT'}]

2019-10-10

[array(['Brzycki', 'Bryan', ''], dtype=object) array(['Siemion', 'Andrew P. V.', ''], dtype=object) array(['Croft', 'Steve', ''], dtype=object) array(['Czech', 'Daniel', ''], dtype=object) array(['DeBoer', 'David', ''], dtype=object) array(['DeMarines', 'Julia', ''], dtype=object) array(['Drew', 'Jamie', ''], dtype=object) array(['Enriquez', 'J. Emilio', ''], dtype=object) array(['Gajjar', 'Vishal', ''], dtype=object) array(['Gizani', 'Nectaria', ''], dtype=object) array(['Isaacson', 'Howard', ''], dtype=object) array(['Lacki', 'Brian C.', ''], dtype=object) array(['Lebofsky', 'Matt', ''], dtype=object) array(['MacMahon', 'David H. E.', ''], dtype=object) array(['de Pater', 'Imke', ''], dtype=object) array(['Price', 'Daniel C.', ''], dtype=object) array(['Sheikh', 'Sofia Z.', ''], dtype=object) array(['Webb', 'Claire', ''], dtype=object) array(['Worden', 'S. Pete', ''], dtype=object)]

nlin/0702013

Vasyl Gafiychuk

V.Gafiychuk, B.Datsko, V.Meleshko

Nonlinear oscillations and stability domains in fractional reaction-diffusion systems

15 pages, 5 figures

nlin.PS nlin.AO

We study a fractional reaction-diffusion system with two types of variables: activator and inhibitor. The interactions between components are modeled by cubical nonlinearity. Linearization of the system around the homogeneous state provides information about the stability of the solutions which is quite different from linear stability analysis of the regular system with integer derivatives. It is shown that by combining the fractional derivatives index with the ratio of characteristic times, it is possible to find the marginal value of the index where the oscillatory instability arises. The increase of the value of fractional derivative index leads to the time periodic solutions. The domains of existing of periodic solutions for different parameters of the problem are obtained. A computer simulation of the corresponding nonlinear fractional ordinary differential equations is presented. It is established by computer simulation that there exists a set of stable spatio-temporal tructures of the one-dimensional system under the Neumann and periodic boundary condition. The features of these solutions consist in the transformation of the steady state dissipative structures to homogeneous oscillations or space temporary structures at a certain value of fractional index and the ratio of characteristic times of system.

[{'version': 'v1', 'created': 'Wed, 7 Feb 2007 14:38:33 GMT'}]

2007-05-23

[array(['Gafiychuk', 'V.', ''], dtype=object) array(['Datsko', 'B.', ''], dtype=object) array(['Meleshko', 'V.', ''], dtype=object)]

1801.00562

Masaaki Kimura

Y. Chiba and M. Kimura

Hoyle-analogue state in 13C studied with Antisymmetrized Molecular Dynamics

Phys. Rev. C 101, 024317 (2020)

10.1103/PhysRevC.101.024317

nucl-th nucl-ex

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

The cluster states in $^{13}{\rm C}$ are investigated by antisymmetrized molecular dynamics. By investigating the spectroscopic factors, the cluster configurations of the excited states are discussed. It is found that the $1/2^+_2$ state is dominantly composed of the $^{12}{\rm C}(0^+_2)\otimes s_{1/2}$ configuration and can be regarded as a Hoyle analogue state. On the other hand, the p-wave states ($3/2^-$ and $1/2^-$) do not have such structure, because of the coupling with other configurations. The isoscalar monopole and dipole transition strengths from the ground to the excited states are also studied. It is shown that the excited $1/2^-$ states have strong isoscalar monopole transition strengths consistent with the observation. On the other hand, the excited $1/2^+$ states unexpectedly have weak isoscalar dipole transitions except for the $1/2^+_1$ state. It is discussed that the suppression of the dipole transition is attributed to the property of the dipole operator.

[{'version': 'v1', 'created': 'Tue, 2 Jan 2018 07:11:19 GMT'}]

2020-03-04

[array(['Chiba', 'Y.', ''], dtype=object) array(['Kimura', 'M.', ''], dtype=object)]

1805.07586

Giuseppe Greco

Sabine Frittella, Giuseppe Greco, Alexander Kurz, Alessandra Palmigiano, Vlasta Sikimi\'c

Multi-type Display Calculus for Dynamic Epistemic Logic

Journal of Logic and Computation, Volume 26, Issue 6, 1 December 2016, Pages 2017--2065

10.1093/logcom/exu068

math.LO

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

In the present paper, we introduce a multi-type display calculus for dynamic epistemic logic, which we refer to as Dynamic Calculus. The display-approach is suitable to modularly chart the space of dynamic epistemic logics on weaker-than-classical propositional base. The presence of types endows the language of the Dynamic Calculus with additional expressivity, allows for a smooth proof-theoretic treatment, and paves the way towards a general methodology for the design of proof systems for the generality of dynamic logics, and certainly beyond dynamic epistemic logic. We prove that the Dynamic Calculus adequately captures Baltag-Moss-Solecki's dynamic epistemic logic, and enjoys Belnap-style cut elimination.

[{'version': 'v1', 'created': 'Sat, 19 May 2018 12:59:37 GMT'}]

2018-05-22

[array(['Frittella', 'Sabine', ''], dtype=object) array(['Greco', 'Giuseppe', ''], dtype=object) array(['Kurz', 'Alexander', ''], dtype=object) array(['Palmigiano', 'Alessandra', ''], dtype=object) array(['Sikimić', 'Vlasta', ''], dtype=object)]

0708.2271

Vladislav V. Kravchenko

Vladislav V. Kravchenko

Solution of the equation d/dx(pdu/dx)+qu=cu by a solution of the equation d/dx(pdu/dx)+qu=0

Published under the title: A representation for solutions of the Sturm-Liouville equation. Complex Variables and Elliptic Problems, 2008, v. 53, No. 8, 775-789

math-ph math.MP

We give a simple solution of the equation d/dx(pdu/dx)+qu=cu whenever a nontrivial solution of d/dx(pdu/dx)+qu=0 is known. The method developed for obtaining this result is based on the theory of pseudoanalytic functions and their relationship with solutions of the stationary two-dimensional Schrodinger equation. The final result, that is the formula for the general solution of the equation d/dx(pdu/dx)+qu=cu has a simple and easily verifiable form.

[{'version': 'v1', 'created': 'Thu, 16 Aug 2007 19:44:00 GMT'} {'version': 'v2', 'created': 'Mon, 7 Jan 2008 17:57:42 GMT'}]

2010-07-09

[array(['Kravchenko', 'Vladislav V.', ''], dtype=object)]

1501.01237

Jan Verhoeven

Jan Verhoeven, Thomas Wieseh\"ofer, Stephan Stellmach

Anelastic Versus Fully Compressible Turbulent Rayleigh-B\'enard Convection

24 pages, 9 figures

10.1088/0004-637X/805/1/62

astro-ph.SR

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

Numerical simulations of turbulent Rayleigh-B\'enard convection in an ideal gas, using either the anelastic approximation or the fully compressible equations, are compared. Theoretically, the anelastic approximation is expected to hold in weakly superadiabatic systems with $\epsilon = \Delta T / T_r \ll 1$, where $\Delta T$ denotes the superadiabatic temperature drop over the convective layer and $T_r$ the bottom temperature. Using direct numerical simulations, a systematic comparison of anelastic and fully compressible convection is carried out. With decreasing superadiabaticity $\epsilon$, the fully compressible results are found to converge linearly to the anelastic solution with larger density contrasts generally improving the match. We conclude that in many solar and planetary applications, where the superadiabaticity is expected to be vanishingly small, results obtained with the anelastic approximation are in fact more accurate than fully compressible computations, which typically fail to reach small $\epsilon$ for numerical reasons. On the other hand, if the astrophysical system studied contains $\epsilon\sim O(1)$ regions, such as the solar photosphere, fully compressible simulations have the advantage of capturing the full physics. Interestingly, even in weakly superadiabatic regions, like the bulk of the solar convection zone, the errors introduced by using artificially large values for $\epsilon$ for efficiency reasons remain moderate. If quantitative errors of the order of $10\%$ are acceptable in such low $\epsilon$ regions, our work suggests that fully compressible simulations can indeed be computationally more efficient than their anelastic counterparts.

[{'version': 'v1', 'created': 'Tue, 6 Jan 2015 17:02:24 GMT'} {'version': 'v2', 'created': 'Fri, 13 Mar 2015 15:10:42 GMT'}]

2015-05-27

[array(['Verhoeven', 'Jan', ''], dtype=object) array(['Wiesehöfer', 'Thomas', ''], dtype=object) array(['Stellmach', 'Stephan', ''], dtype=object)]

hep-ph/0602148

Giacomo Morpurgo

G.Dillon and G.Morpurgo

The contribution of strange quarks to the proton magnetic moment

11 pages, 1 eps figure

GEF-TH-02/2006

hep-ph

This paper deals with how to extract the s-s(bar) contribution to the proton magnetic moment from the experiments

[{'version': 'v1', 'created': 'Thu, 16 Feb 2006 11:46:22 GMT'} {'version': 'v2', 'created': 'Mon, 20 Feb 2006 11:15:08 GMT'}]

2007-05-23

[array(['Dillon', 'G.', ''], dtype=object) array(['Morpurgo', 'G.', ''], dtype=object)]

1812.08251

Jimmy Mc Laughlin

Doug Bowman and James Mc Laughlin

Polynomial Continued Fractions

13 pages

Acta Arith. 103 (2002), no. 4, 329--342

10.4064/aa103-4-3

math.NT

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

Continued fractions whose elements are polynomial sequences have been carefully studied mostly in the cases where the degree of the numerator polynomial is less than or equal to two and the degree of the denominator polynomial is less than or equal to one. Here we study cases of higher degree for both numerator and denominator polynomials, with particular attention given to cases in which the degrees are equal. We extend work of Ramanujan on continued fractions with rational limits and also consider cases where the limits are irrational.

[{'version': 'v1', 'created': 'Wed, 19 Dec 2018 21:28:02 GMT'}]

2018-12-26

[array(['Bowman', 'Doug', ''], dtype=object) array(['Laughlin', 'James Mc', ''], dtype=object)]

1410.1219

Jonathan Rollin

Maria Axenovich, Jonathan Rollin

Brooks Type Results for Conflict-Free Colorings and {a, b}-factors in graphs

Fixed typos in statement of Theorem 7; 9 pages, 1 figure

Discrete Mathematics 338(12):2295--2301, 2015

math.CO

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

A vertex-coloring of a hypergraph is conflict-free, if each edge contains a vertex whose color is not repeated on any other vertex of that edge. Let $f(r, \Delta)$ be the smallest integer $k$ such that each $r$-uniform hypergraph of maximum vertex degree $\Delta$ has a conflict-free coloring with at most $k$ colors. As shown by Tardos and Pach, similarly to a classical Brooks' type theorem for hypergraphs, $f(r, \Delta)\leq \Delta+1$. Compared to Brooks' theorem, according to which there is only a couple of graphs/hypergraphs that attain the $\Delta+1$ bound, we show that there are several infinite classes of uniform hypergraphs for which the upper bound is attained. We provide bounds on $f(r, \Delta)$ in terms of~$\Delta$ for large~$\Delta$ and establish the connection between conflict-free colorings and so-called $\{t, r-t\}$-factors in $r$-regular graphs. Here, a $\{t, r-t\}$-factor is a factor in which each degree is either $t$ or $r-t$. Among others, we disprove a conjecture of Akbari and Kano~[Graphs and Combinatorics 30(4):821--826, 2014] stating that there is a $\{t,r-t\}$-factor in every $r$-regular graph for odd $r$ and any odd $t<\frac{r}{3}$.

[{'version': 'v1', 'created': 'Sun, 5 Oct 2014 22:47:53 GMT'} {'version': 'v2', 'created': 'Mon, 5 Dec 2016 10:35:21 GMT'}]

2016-12-06

[array(['Axenovich', 'Maria', ''], dtype=object) array(['Rollin', 'Jonathan', ''], dtype=object)]

1307.0330

Mohammad Hassan Vahidinia

M. H. Dehghani, M. H. Vahidinia

Quartic Quasi-topological Gravity, Black Holes and Holography

27 pages, 14 figures, minor typos corrected, a comment on bulk causality is added, updated to published version

JHEP, 10(2013)210

10.1007/JHEP10(2013)210

hep-th

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

In this paper, we derive the field equations of quartic quasi-topological gravity by varying the action with respect to the metric. Also, we obtain the linearized graviton equations in the AdS background and find that it is governed by a second-order field equation as in the cases of Einstein, Lovelock or cubic quasi-topological gravities. But in contrast to the cubic quasi-topological gravity, the linearized field equation around a black hole has fourth-order radial derivative of the perturbation. Moreover, we analyze the conditions of having ghost free AdS solutions and AdS planar black holes. In addition, we compute the central charges of the dual conformal field theory of this gravity theory by studying holographic Weyl anomaly. Finally, we consider the effect of quartic term on the causality of dual theory in the tensor channel and show that, in the contrast to the trivial result of cubic quasi-topological gravity, the existence of both cubic and quartic terms leads to a non-trivial constraint. However, this constraint does not imply any lower positive bound on the viscosity/entropy ratio.

[{'version': 'v1', 'created': 'Mon, 1 Jul 2013 10:56:07 GMT'} {'version': 'v2', 'created': 'Mon, 11 Nov 2013 09:10:14 GMT'}]

2013-11-12

[array(['Dehghani', 'M. H.', ''], dtype=object) array(['Vahidinia', 'M. H.', ''], dtype=object)]

1802.08918

Linyuan Lu

Linyuan Lu and Zhiyu Wang

Anti-Ramsey number of edge-disjoint rainbow spanning trees

17 pages, fixed an error in the proof of Theorem 3 using Matroid methods

math.CO

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

An edge-colored graph $G$ is called rainbow if every edge of $G$ receives a different color. The anti-Ramsey number of $t$ edge-disjoint rainbow spanning trees, denoted by $r(n,t)$, is defined as the maximum number of colors in an edge-coloring of $K_n$ containing no $t$ edge-disjoint rainbow spanning trees. Jahanbekam and West [J. Graph Theory, 2014] conjectured that for any fixed $t$, $r(n,t)=\binom{n-2}{2}+t$ whenever $n\geq 2t+2 \geq 6$. In this paper, we prove this conjecture. We also determine $r(n,t)$ when $n = 2t+1$. Together with previous results, this gives the anti-Ramsey number of $t$ edge-disjoint rainbow spanning trees for all values of $n$ and $t$.

[{'version': 'v1', 'created': 'Sat, 24 Feb 2018 21:37:07 GMT'} {'version': 'v2', 'created': 'Thu, 14 Nov 2019 15:45:16 GMT'} {'version': 'v3', 'created': 'Sat, 16 Nov 2019 20:46:32 GMT'}]

2019-11-19

[array(['Lu', 'Linyuan', ''], dtype=object) array(['Wang', 'Zhiyu', ''], dtype=object)]

2204.02750

Yuzhi Shi Prof.

Yuzhi Shi, Qinghua Song, Ivan Toftul, Tongtong Zhu, Yefeng Yu, Weiming Zhu, Din Ping Tsai, Yuri Kivshar and Ai Qun Liu

Optical manipulation with metamaterial structures

49 pages, 5 figures

physics.optics physics.app-ph

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

Optical tweezers employing forces produced by light underpin important manipulation tools in many areas of applied and biological physics. Conventional optical tweezers are based on refractive optics, and they require excessive auxiliary optical elements to reshape both amplitude and phase, as well as wavevector and angular momentum of light, and thus impose limitations to the overall cost and integration of optical systems. Metamaterials provide both electric and optically induced magnetic response in subwavelength optical structures, and they are highly beneficial to achieve unprecedented control of light required for many applications, also opening new opportunities for optical manipulation. Here, we review the recent advances in the field of optical tweezers employing the physics and concepts of metamaterials (the so-called meta-tweezers) and demonstrate that metamaterial structures could not only advance classical operations with particles, such as trapping, transporting, and sorting, but they uncover exotic optical forces such as pulling and lateral forces. Remarkably, apart from manipulation of particles, metastructures can be powered dynamically by light to realize ingenious meta-robots. We provide an outlook for future opportunities in this area ranging from enhanced particle manipulation to meta-robot actuation.

[{'version': 'v1', 'created': 'Wed, 6 Apr 2022 11:49:03 GMT'}]

2022-04-07

[array(['Shi', 'Yuzhi', ''], dtype=object) array(['Song', 'Qinghua', ''], dtype=object) array(['Toftul', 'Ivan', ''], dtype=object) array(['Zhu', 'Tongtong', ''], dtype=object) array(['Yu', 'Yefeng', ''], dtype=object) array(['Zhu', 'Weiming', ''], dtype=object) array(['Tsai', 'Din Ping', ''], dtype=object) array(['Kivshar', 'Yuri', ''], dtype=object) array(['Liu', 'Ai Qun', ''], dtype=object)]

2010.00859

Kim Myung-Whun

Purevdorj Munkhbaatar and Kim Myung-Whun

Origin of the mid-infrared peaks in the optical conductivity of LaMnO$_{3}$

10 pages, 3 figures

10.1016/j.ssc.2021.114381

cond-mat.str-el

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

We calculated the infrared conductivity spectrum of orbitally ordered LaMnO$_3$ in phonon frequency and overtone frequency ranges. We considered orbital exchange, Jahn-Teller electron-phonon coupling, and phonon--phonon coupling. The fundamental excitation of the phonon-coupled orbiton was only Raman active, not infrared active, while its overtone modes were both Raman and infrared active. Our calculations reproduced the small peaks near 1300 cm$^{-1}$ observed both in Raman scattering and infrared conductivity spectra, as consistent with previous experimental results.

[{'version': 'v1', 'created': 'Fri, 2 Oct 2020 08:41:21 GMT'} {'version': 'v2', 'created': 'Sat, 15 May 2021 03:07:47 GMT'}]

2021-06-30

[array(['Munkhbaatar', 'Purevdorj', ''], dtype=object) array(['Myung-Whun', 'Kim', ''], dtype=object)]

1609.06804

Zhouyuan Huo

Zhouyuan Huo, Bin Gu, Heng Huang

Decoupled Asynchronous Proximal Stochastic Gradient Descent with Variance Reduction

cs.LG math.OC

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

In the era of big data, optimizing large scale machine learning problems becomes a challenging task and draws significant attention. Asynchronous optimization algorithms come out as a promising solution. Recently, decoupled asynchronous proximal stochastic gradient descent (DAP-SGD) is proposed to minimize a composite function. It is claimed to be able to off-loads the computation bottleneck from server to workers by allowing workers to evaluate the proximal operators, therefore, server just need to do element-wise operations. However, it still suffers from slow convergence rate because of the variance of stochastic gradient is nonzero. In this paper, we propose a faster method, decoupled asynchronous proximal stochastic variance reduced gradient descent method (DAP-SVRG). We prove that our method has linear convergence for strongly convex problem. Large-scale experiments are also conducted in this paper, and results demonstrate our theoretical analysis.

[{'version': 'v1', 'created': 'Thu, 22 Sep 2016 02:50:09 GMT'} {'version': 'v2', 'created': 'Thu, 29 Sep 2016 01:54:25 GMT'}]

2016-09-30

[array(['Huo', 'Zhouyuan', ''], dtype=object) array(['Gu', 'Bin', ''], dtype=object) array(['Huang', 'Heng', ''], dtype=object)]

1812.08117

Daniel Ruprecht

Krasymyr Tretiak and Daniel Ruprecht

An arbitrary order time-stepping algorithm for tracking particles in inhomogeneous magnetic fields

Journal of Computational Physics: X 4, pp. 100036, 2019

10.1016/j.jcpx.2019.100036

math.NA cs.CE cs.NA

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

The Lorentz equations describe the motion of electrically charged particles in electric and magnetic fields and are used widely in plasma physics. The most popular numerical algorithm for solving them is the Boris method, a variant of the St\"ormer-Verlet algorithm. Boris' method is phase space volume conserving and simulated particles typically remain near the correct trajectory. However, it is only second order accurate. Therefore, in scenarios where it is not enough to know that a particle stays on the right trajectory but one needs to know where on the trajectory the particle is at a given time, Boris method requires very small time steps to deliver accurate phase information, making it computationally expensive. We derive an improved version of the high-order Boris spectral deferred correction algorithm (Boris-SDC) by adopting a convergence acceleration strategy for second order problems based on the Generalised Minimum Residual (GMRES) method. Our new algorithm is easy to implement as it still relies on the standard Boris method. Like Boris-SDC it can deliver arbitrary order of accuracy through simple changes of runtime parameter but possesses better long-term energy stability. We demonstrate for two examples, a magnetic mirror trap and the Solev'ev equilibrium, that the new method can deliver better accuracy at lower computational cost compared to the standard Boris method. While our examples are motivated by tracking ions in the magnetic field of a nuclear fusion reactor, the introduced algorithm can potentially deliver similar improvements in efficiency for other applications.

[{'version': 'v1', 'created': 'Wed, 19 Dec 2018 17:51:23 GMT'} {'version': 'v2', 'created': 'Fri, 2 Aug 2019 08:29:03 GMT'}]

2019-09-17

[array(['Tretiak', 'Krasymyr', ''], dtype=object) array(['Ruprecht', 'Daniel', ''], dtype=object)]

1111.5822

Ivan Katkov

Ivan Yu. Katkov and Igor V. Chilingarian

Multi-component parametric inversion of galaxy kinematics and stellar populations using full spectral fitting

3 pages, 2 figures; to appear in the proceedings of "The Spectral Energy Distribution of Galaxies", Preston, UK, 5-9 September 2011

10.1017/S1743921312008770

astro-ph.IM

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

The stellar line-of-sight velocity distribution (LOSVD) can be strongly asymmetric in regions where the light contributions of both disc and bulge in spiral and lenticular galaxies are comparable. Existing techniques for the stellar kinematics analysis do not take into account the difference of disc and bulge stellar populations. Here we present a novel approach to the analysis of stellar kinematics and stellar populations. We use a two-component model of spectra where different stellar population components are convolved with pure Gaussian LOSVDs. For this model we present Monte-Carlo simulations demonstrating degeneracies between the parameters.

[{'version': 'v1', 'created': 'Thu, 24 Nov 2011 17:35:29 GMT'}]

2015-06-03

[array(['Katkov', 'Ivan Yu.', ''], dtype=object) array(['Chilingarian', 'Igor V.', ''], dtype=object)]

2001.04403

Craig Lent

Craig S. Lent

Blind witnesses quench quantum interference without transfer of which-path information

6 Figures

Entropy 22, 776 (2020)

10.3390/e22070776

quant-ph

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

We model the fundamental behavior of a two-branch quantum interference device. Quantum interference oscillations are visible in the output as the magnetic flux through the paths is varied. Multiple witness systems are field-coupled to each branch. Each witness state entangles with the device state, but for our {\em blind} witnesses which-path information is not transferred to the quantum state of witnesses--they cannot "see" or make a record of which path is traversed. Yet the presence of these minimal witnesses rapidly quenches quantum interference. Thus, it is not the imprinting of which-path information in the witness states that is essential for decoherence, but simply the entanglement that embeds the device degrees of freedom in the larger Hilbert space that includes the witnesses. The loss of interference visibility can be understood as the result of phase cancellations from different paths through the larger state space.

[{'version': 'v1', 'created': 'Mon, 13 Jan 2020 17:09:36 GMT'}]

2022-03-31

[array(['Lent', 'Craig S.', ''], dtype=object)]

1112.3958

Jay Strader

Jay Strader, Anil C. Seth, Nelson Caldwell

Old Massive Globular Clusters and the Stellar Halo of the Dwarf Starburst Galaxy NGC 4449

15 pages, AJ in press

10.1088/0004-6256/143/2/52

astro-ph.CO astro-ph.GA

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

We use Hubble Space Telescope imaging to show that the nearby dwarf starburst galaxy NGC 4449 has an unusual abundance of luminous red star clusters. Joint constraints from integrated photometry, low-resolution spectroscopy, dynamical mass-to-light ratios, and resolved color-magnitude diagrams provide evidence that some of these clusters are old globular clusters. Spectroscopic data for two massive clusters suggest intermediate metallicities ([Fe/H] ~ -1) and subsolar Mg enhancement ([Mg/Fe] ~ -0.1 to -0.2). One of these clusters may be the nucleus of a tidally disrupting dwarf galaxy; the other is very massive (~ 3 x 10^6 M_sun). We have also identified a population of remote halo globular clusters. NGC 4449 is consistent with an emerging picture of the ubiquity of stellar halos among dwarf galaxies, and study of its globular clusters may help distinguish between accretion and in situ scenarios for such halos.

[{'version': 'v1', 'created': 'Fri, 16 Dec 2011 21:00:00 GMT'}]

2015-06-03

[array(['Strader', 'Jay', ''], dtype=object) array(['Seth', 'Anil C.', ''], dtype=object) array(['Caldwell', 'Nelson', ''], dtype=object)]

quant-ph/9704035

Larry Ford

L.H. Ford

Electromagnetic Vacuum Fluctuations and Electron Coherence II: Effects of Wavepacket Size

16 pages, Latex, 3 figures, uses epsf

Phys.Rev. A56 (1997) 1812-1818

10.1103/PhysRevA.56.1812

TUTP-97-5

quant-ph hep-th

If one analyzes the effects of electromagnetic vacuum fluctuations upon an electron interference pattern in an approximation in which the electrons follow classical trajectories, an ultraviolet divergence results. It is shown that this divergence is an artifact of the classical trajectory approximation, and is absent when the finite sizes of electron wavepackets are accounted for. It is shown that the vacuum fluctuation effect has a logarithmic dependence upon the wavepacket size. However, at least in one model geometry, this dependence cancels when one includes both vacuum fluctuation and photon emission effects.

[{'version': 'v1', 'created': 'Thu, 17 Apr 1997 17:05:23 GMT'}]

2009-10-30

[array(['Ford', 'L. H.', ''], dtype=object)]

1711.08244

Ambrish Rawat

Ambrish Rawat, Martin Wistuba, Maria-Irina Nicolae

Adversarial Phenomenon in the Eyes of Bayesian Deep Learning

13 pages, 7 figures

stat.ML cs.LG

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

Deep Learning models are vulnerable to adversarial examples, i.e.\ images obtained via deliberate imperceptible perturbations, such that the model misclassifies them with high confidence. However, class confidence by itself is an incomplete picture of uncertainty. We therefore use principled Bayesian methods to capture model uncertainty in prediction for observing adversarial misclassification. We provide an extensive study with different Bayesian neural networks attacked in both white-box and black-box setups. The behaviour of the networks for noise, attacks and clean test data is compared. We observe that Bayesian neural networks are uncertain in their predictions for adversarial perturbations, a behaviour similar to the one observed for random Gaussian perturbations. Thus, we conclude that Bayesian neural networks can be considered for detecting adversarial examples.

[{'version': 'v1', 'created': 'Wed, 22 Nov 2017 12:02:53 GMT'}]

2017-11-23

[array(['Rawat', 'Ambrish', ''], dtype=object) array(['Wistuba', 'Martin', ''], dtype=object) array(['Nicolae', 'Maria-Irina', ''], dtype=object)]

0704.2982

Michele Pestalozzi PhD

Michele Pestalozzi

Methanol masers as tools to study high-mass star formation

8 pages, invited talk at the IAU Symposium 242, "Astrophysical masers and their environment"

10.1017/S1743921307012628

astro-ph

In this contribution I will attempt to show that the study of galactic 6.7 and 12.2GHz methanol masers themselves, as opposed to the use of methanol masers as signposts, can yield important conclusions contributing to the understanding of high-mass star formation. Due to their exclusive association with star formation, methanol masers are the best tools to do this, and their large number allows to probe the entire Galaxy. In particular I will focus on the determination of the luminosity function of methanol masers and on the determination of an unambiguous signature for a circumstellar masing disc seen edge-on. Finally I will try to point out some future fields of research in the study of methanol masers.

[{'version': 'v1', 'created': 'Mon, 23 Apr 2007 11:56:57 GMT'}]

2009-11-13

[array(['Pestalozzi', 'Michele', ''], dtype=object)]

1207.3120

Seddik Djouadi Dr.

Seddik M. Djouadi

Optimal Disturbance Rejection and Robustness for Infinite Dimensional LTV Systems

30 pages, 1 figure

math.OC

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

In this paper, we consider the optimal disturbance rejection problem for possibly infinite dimensional linear time-varying (LTV) systems using a framework based on operator algebras of classes of bounded linear operators. This approach does not assume any state space representation and views LTV systems as causal operators. After reducing the problem to a shortest distance minimization in a space of bounded linear operators, duality theory is applied to show existence of optimal solutions, which satisfy a "time-varying" allpass or flatness condition. Under mild assumptions the optimal TV controller is shown to be essentially unique. Next, the concept of M-ideals of operators is used to show that the computation of time-varying (TV) controllers reduces to a search over compact TV Youla parameters. This involves the norm of a TV compact Hankel operator defined on the space of causal trace-class 2 operators and its maximal vectors. Moreover, an operator identity to compute the optimal TV Youla parameter is provided. These results are generalized to the mixed sensitivity problem for TV systems as well, where it is shown that the optimum is equal to the operator induced of a TV mixed Hankel-Toeplitz. The final outcome of the approach developed here is that it leads to two tractable finite dimensional convex optimizations producing estimates to the optimum within desired tolerances, and a method to compute optimal time-varying controllers.

[{'version': 'v1', 'created': 'Thu, 12 Jul 2012 23:26:57 GMT'}]

2012-07-16

[array(['Djouadi', 'Seddik M.', ''], dtype=object)]

cond-mat/9911140

Bruno Bassetti

B.Bassetti, M.Cosentino Lagomarsino, P.Jona

A Model for the Self-Organization of Microtubules Driven by Molecular Motors

23 pages, 10 figures, LaTeX, eps

10.1007/s100510051150

cond-mat.stat-mech

We propose a two-dimensional model for the organization of stabilized microtubules driven by molecular motors in an unconfined geometry. In this model two kinds of dynamics are competing. The first one is purely diffusive, with an interaction between the rotational degrees of freedom, the second one is a local drive, dependent on microtubule polarity. As a result, there is a configuration dependent driving field. Applying a molecular field approximation, we are able to derive continuum equations. A study on the solutions shows nonequilibrium steady states. The presence and stability of such self-organized states are investigated in terms of entropy production. Numerical simulations confirm analytical results.

[{'version': 'v1', 'created': 'Wed, 10 Nov 1999 14:26:44 GMT'}]

2019-08-17

[array(['Bassetti', 'B.', ''], dtype=object) array(['Lagomarsino', 'M. Cosentino', ''], dtype=object) array(['Jona', 'P.', ''], dtype=object)]

math/0202136

James Allen Fill

Keith Crank (National Science Foundation), James Allen Fill (Johns Hopkins Univ.)

Interruptible exact sampling in the passive case

17 pages. See also http://www.mts.jhu.edu/~fill/ . To be submitted for publication in spring, 2002

632, Department of Mathematical Sciences, The Johns Hopkins University

math.PR math.ST stat.TH

We establish, for various scenarios, whether or not interruptible exact stationary sampling is possible when a finite-state Markov chain can only be viewed passively. In particular, we prove that such sampling is not possible using a single copy of the chain. Such sampling is possible when enough copies of the chain are available, and we provide an algorithm that terminates with probability one.

[{'version': 'v1', 'created': 'Thu, 14 Feb 2002 20:51:17 GMT'}]

2007-06-13

[array(['Crank', 'Keith', '', 'National Science Foundation'], dtype=object) array(['Fill', 'James Allen', '', 'Johns\n Hopkins Univ.'], dtype=object)]

2203.12437

Oliver Keszocze

Jan Sommer, M. Akif \"Ozkan, Oliver Keszocze, J\"urgen Teich

Efficient Hardware Acceleration of Sparsely Active Convolutional Spiking Neural Networks

12 pages, 12 figures, 5 tables, submitted to CODES 2022

10.1109/TCAD.2022.3197512

cs.AR cs.NE

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

Spiking Neural Networks (SNNs) compute in an event-based matter to achieve a more efficient computation than standard Neural Networks. In SNNs, neuronal outputs (i.e. activations) are not encoded with real-valued activations but with sequences of binary spikes. The motivation of using SNNs over conventional neural networks is rooted in the special computational aspects of SNNs, especially the very high degree of sparsity of neural output activations. Well established architectures for conventional Convolutional Neural Networks (CNNs) feature large spatial arrays of Processing Elements (PEs) that remain highly underutilized in the face of activation sparsity. We propose a novel architecture that is optimized for the processing of Convolutional SNNs (CSNNs) that feature a high degree of activation sparsity. In our architecture, the main strategy is to use less but highly utilized PEs. The PE array used to perform the convolution is only as large as the kernel size, allowing all PEs to be active as long as there are spikes to process. This constant flow of spikes is ensured by compressing the feature maps (i.e. the activations) into queues that can then be processed spike by spike. This compression is performed in run-time using dedicated circuitry, leading to a self-timed scheduling. This allows the processing time to scale directly with the number of spikes. A novel memory organization scheme called memory interlacing is used to efficiently store and retrieve the membrane potentials of the individual neurons using multiple small parallel on-chip RAMs. Each RAM is hardwired to its PE, reducing switching circuitry and allowing RAMs to be located in close proximity to the respective PE. We implemented the proposed architecture on an FPGA and achieved a significant speedup compared to other implementations while needing less hardware resources and maintaining a lower energy consumption.

[{'version': 'v1', 'created': 'Wed, 23 Mar 2022 14:18:58 GMT'}]

2023-06-23

[array(['Sommer', 'Jan', ''], dtype=object) array(['Özkan', 'M. Akif', ''], dtype=object) array(['Keszocze', 'Oliver', ''], dtype=object) array(['Teich', 'Jürgen', ''], dtype=object)]

quant-ph/0603076

Pawel Maslanka

Bartosz Zielinski, Magdalena Zych

A generalization of Margolus-Levitin bound

6 pages, no figures; some comments added; final version accepted for publication in Phys. Rev. A

10.1103/PhysRevA.74.034301

quant-ph

The Margolus-Levitin lower bound on minimal time required for a state to be transformed into an orthogonal state is generalized. It is shown that for some initial states new bound is stronger than the Margolus-Levitin one.

[{'version': 'v1', 'created': 'Thu, 9 Mar 2006 12:49:11 GMT'} {'version': 'v2', 'created': 'Fri, 10 Mar 2006 10:05:47 GMT'} {'version': 'v3', 'created': 'Wed, 17 May 2006 13:10:13 GMT'} {'version': 'v4', 'created': 'Fri, 18 Aug 2006 12:45:53 GMT'}]

2009-11-13

[array(['Zielinski', 'Bartosz', ''], dtype=object) array(['Zych', 'Magdalena', ''], dtype=object)]

2112.14293

Babak Seradjeh

Alan Kostelecky, Ralf Lehnert, Navin McGinnis, Marco Schreck, Babak Seradjeh

Lorentz violation in Dirac and Weyl semimetals

18 pages, 7 figures. We welcome all feedback!

Physical Review Research 4, 023106 (2022)

10.1103/PhysRevResearch.4.023106

cond-mat.mes-hall cond-mat.mtrl-sci cond-mat.str-el hep-ph hep-th

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

We propose a correspondence between the description of emergent Lorentz symmetry in condensed-matter systems and the established general effective field theory for Lorentz violation in fundamental theories of spacetime and matter. This correspondence has potential implications in both directions. We illustrate the proposal by investigating its consequences for the spectral and transport properties of Dirac and Weyl semimetals. Particular realizations of this framework give rise to Dirac nodal spectra with nodal lines and rings. We demonstrate a bulk-boundary correspondence between bulk topological invariants and drumhead surface states of these Dirac nodal semimetals. We calculate their transport coefficients in leading-order perturbation theory, thereby characterizing the unconventional electromagnetic response due to small deviations from emergent Lorentz invariance. Some prospective future applications of the correspondence are outlined.

[{'version': 'v1', 'created': 'Tue, 28 Dec 2021 20:52:43 GMT'}]

2022-07-08

[array(['Kostelecky', 'Alan', ''], dtype=object) array(['Lehnert', 'Ralf', ''], dtype=object) array(['McGinnis', 'Navin', ''], dtype=object) array(['Schreck', 'Marco', ''], dtype=object) array(['Seradjeh', 'Babak', ''], dtype=object)]

1807.00715

Avinash Surendran Mr.

Avinash Surendran, Mahesh P. Burse, A. N. Ramaprakash, Padmakar S. Parihar

Scalable Platform for Adaptive optics Real-time Control (SPARC) Part 2: Field Programmable Gate Array (FPGA) implementation and performance

19 pages, 6 figures, accepted in JATIS (SPIE)

10.1117/1.JATIS.4.3.039002

astro-ph.IM

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

The next generation of Adaptive Optics (AO) systems on large telescopes will require immense computation performance and memory bandwidth, both of which are challenging with the technology available today. The objective of this work is to create a future-proof adaptive optics platform on an FPGA architecture, which scales with the number of subapertures, pixels per subaperture and external memory. We have created a scalable adaptive optics platform with an off-the-shelf FPGA development board, which provides an AO reconstruction time only limited by the external memory bandwidth. SPARC uses the same logic resources irrespective of the number of subapertures in the AO system. This paper is aimed at embedded developers who are interested in the FPGA design and the accompanying hardware interfaces. The central theme of this paper is to show how scalability is incorporated at different levels of the FPGA implementation. This work is a continuation of Part 1 of the paper which explains the concept, objectives, control scheme and method of validation used for testing the platform.

[{'version': 'v1', 'created': 'Mon, 2 Jul 2018 14:44:31 GMT'}]

2018-08-03

[array(['Surendran', 'Avinash', ''], dtype=object) array(['Burse', 'Mahesh P.', ''], dtype=object) array(['Ramaprakash', 'A. N.', ''], dtype=object) array(['Parihar', 'Padmakar S.', ''], dtype=object)]

2303.15794

Kana Moriwaki

Kana Moriwaki, Takahiro Nishimichi, Naoki Yoshida

Machine Learning for Observational Cosmology

55 pages, 8 figures, accepted for publication in Reports on Progress in Physics

10.1088/1361-6633/acd2ea

YITP-23-40

astro-ph.IM astro-ph.CO astro-ph.GA astro-ph.HE

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

An array of large observational programs using ground-based and space-borne telescopes is planned in the next decade. The forthcoming wide-field sky surveys are expected to deliver a sheer volume of data exceeding an exabyte. Processing the large amount of multiplex astronomical data is technically challenging, and fully automated technologies based on machine learning and artificial intelligence are urgently needed. Maximizing scientific returns from the big data requires community-wide efforts. We summarize recent progress in machine learning applications in observational cosmology. We also address crucial issues in high-performance computing that are needed for the data processing and statistical analysis.

[{'version': 'v1', 'created': 'Tue, 28 Mar 2023 07:59:04 GMT'} {'version': 'v2', 'created': 'Thu, 25 May 2023 06:44:05 GMT'}]

2023-05-26

[array(['Moriwaki', 'Kana', ''], dtype=object) array(['Nishimichi', 'Takahiro', ''], dtype=object) array(['Yoshida', 'Naoki', ''], dtype=object)]

2210.13809

Yuuki Shida

Yuuki Shida and Masami Sugawara and Ryosuke Tsumura and Haruaki Chiba and Tokuhisa Uejima and Hiroyasu Iwata

Diagnostic Posture Control System for Seated-Style Echocardiography Robot

cs.RO

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

Purpose: Conventional robotic ultrasound systems were utilized with patients in supine positions. Meanwhile, the limitation of the systems is that it is difficult to evacuate the patients in case of emergency (e.g., patient discomfort and system failure) because the patients are restricted between the robot system and bed. Then, it is ideal that the patient undergoes the examination in the sitting position in terms of safety. Therefore, we validated a feasibility study of seated-style echocardiography using a robot. Method: Preliminary experiments were conducted to verify the following two points: (1) the possibility of obtaining cardiac disease features in the sitting posture as well as in the conventional examination, and (2) the relationship between posture angle and physical burden. For reducing the physical burden, two unique mechanisms were incorporated into the system: (1) a leg pendulum base mechanism to reduce the load on the legs when the lateral bending angle increases, and (2) a roll angle division by a lumbar lateral bending and thoracic rotation mechanisms. Results: Preliminary results demonstrated that adjusting the diagnostic posture angle enabled us to obtain the views, including cardiac disease features, as in the conventional examination. The results showed that the body burden increased as the posture's lateral bending angle increased. The results also demonstrated that the body load reduction mechanism incorporated in the results could reduce the physical load in the seated echocardiography. Conclusion: These results showed the potential of the seated-style echocardiography robot.

[{'version': 'v1', 'created': 'Tue, 25 Oct 2022 07:35:42 GMT'}]

2022-10-26

[array(['Shida', 'Yuuki', ''], dtype=object) array(['Sugawara', 'Masami', ''], dtype=object) array(['Tsumura', 'Ryosuke', ''], dtype=object) array(['Chiba', 'Haruaki', ''], dtype=object) array(['Uejima', 'Tokuhisa', ''], dtype=object) array(['Iwata', 'Hiroyasu', ''], dtype=object)]

1906.09037

Xintao Huan

Xintao Huan, Kyeong Soo Kim, Sanghyuk Lee, Eng Gee Lim, Alan Marshall

A Beaconless Asymmetric Energy-Efficient Time Synchronization Scheme for Resource-Constrained Multi-Hop Wireless Sensor Networks

12 pages, 16 figures

cs.NI cs.PF

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

The ever-increasing number of WSN deployments based on a large number of battery-powered, low-cost sensor nodes, which are limited in their computing and power resources, puts the focus of WSN time synchronization research on three major aspects, i.e., accuracy, energy consumption and computational complexity. In the literature, the latter two aspects have not received much attention compared to the accuracy of WSN time synchronization. Especially in multi-hop WSNs, intermediate gateway nodes are overloaded with tasks for not only relaying messages but also a variety of computations for their offspring nodes as well as themselves. Therefore, not only minimizing the energy consumption but also lowering the computational complexity while maintaining the synchronization accuracy is crucial to the design of time synchronization schemes for resource-constrained sensor nodes. In this paper, focusing on the three aspects of WSN time synchronization, we introduce a framework of reverse asymmetric time synchronization for resource-constrained multi-hop WSNs and propose a beaconless energy-efficient time synchronization scheme based on reverse one-way message dissemination. Experimental results with a WSN testbed based on TelosB motes running TinyOS demonstrate that the proposed scheme conserves up to 95% energy consumption compared to the flooding time synchronization protocol while achieving microsecond-level synchronization accuracy.

[{'version': 'v1', 'created': 'Fri, 21 Jun 2019 10:01:11 GMT'}]

2019-06-24

[array(['Huan', 'Xintao', ''], dtype=object) array(['Kim', 'Kyeong Soo', ''], dtype=object) array(['Lee', 'Sanghyuk', ''], dtype=object) array(['Lim', 'Eng Gee', ''], dtype=object) array(['Marshall', 'Alan', ''], dtype=object)]

2006.00162

John Clemens

John D. Clemens

Relative primeness and Borel partition properties for equivalence relations

Revised version to appear in Transactions of the American Mathematical Society

math.LO

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

We introduce a notion of relative primeness for equivalence relations, strengthening the notion of non-reducibility, and show for many standard benchmark equivalence relations that non-reducibility may be strengthened to relative primeness. We introduce several analogues of cardinal properties for Borel equivalence relations, including the notion of a prime equivalence relation and Borel partition properties on quotient spaces. In particular, we introduce a notion of Borel weak compactness, and characterize partition properties for the equivalence relations ${\mathbb F}_2$ and ${\mathbb E}_1$. We also discuss dichotomies related to primeness, and see that many natural questions related to Borel reducibility of equivalence relations may be viewed in the framework of relative primeness and Borel partition properties.

[{'version': 'v1', 'created': 'Sat, 30 May 2020 03:50:32 GMT'} {'version': 'v2', 'created': 'Fri, 16 Apr 2021 22:47:13 GMT'}]

2021-04-20

[array(['Clemens', 'John D.', ''], dtype=object)]

1412.2053

Erhan Bayraktar

Erhan Bayraktar and Song Yao

Doubly Reflected BSDEs with Integrable Parameters and Related Dynkin Games

Final version. To appear in Stochastic Processes and Their Applications

math.PR math.OC q-fin.MF

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

We study a doubly reflected backward stochastic differential equation (BSDE) with integrable parameters and the related Dynkin game. When the lower obstacle $L$ and the upper obstacle $U$ of the equation are completely separated, we construct a unique solution of the doubly reflected BSDE by pasting local solutions and show that the $Y-$component of the unique solution represents the value process of the corresponding Dynkin game under $g-$evaluation, a nonlinear expectation induced by BSDEs with the same generator $g$ as the doubly reflected BSDE concerned. In particular, the first time when process $Y $ meets $L$ and the first time when process $Y $ meets $U$ form a saddle point of the Dynkin game.

[{'version': 'v1', 'created': 'Fri, 5 Dec 2014 16:42:50 GMT'} {'version': 'v2', 'created': 'Sun, 5 Jul 2015 19:26:27 GMT'}]

2015-07-07

[array(['Bayraktar', 'Erhan', ''], dtype=object) array(['Yao', 'Song', ''], dtype=object)]

0709.3927

R\'obert Juh\'asz

F. Igl\'oi and R. Juh\'asz

Exact relationship between the entanglement entropies of XY and quantum Ising chains

6 pages

Europhys. Lett. 81, 57003 (2008)

10.1209/0295-5075/81/57003

cond-mat.stat-mech quant-ph

We consider two prototypical quantum models, the spin-1/2 XY chain and the quantum Ising chain and study their entanglement entropy, S(l,L), of blocks of l spins in homogeneous or inhomogeneous systems of length L. By using two different approaches, free-fermion techniques and perturbational expansion, an exact relationship between the entropies is revealed. Using this relation we translate known results between the two models and obtain, among others, the additive constant of the entropy of the critical homogeneous quantum Ising chain and the effective central charge of the random XY chain.

[{'version': 'v1', 'created': 'Tue, 25 Sep 2007 11:53:50 GMT'} {'version': 'v2', 'created': 'Tue, 5 Feb 2008 17:20:59 GMT'}]

2009-11-13

[array(['Iglói', 'F.', ''], dtype=object) array(['Juhász', 'R.', ''], dtype=object)]

1706.08846

Riaz Ahmed

G. Abbas, Riaz Ahmed

Models of Collapsing and Expanding Anisotropic Gravitating Source in $f(R,T)$ Theory of Gravity

18 Pages, 8 Figures, Accepted for Publication in European Physical Journal C

10.1140/epjc/s10052-017-5025-0

gr-qc

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

In this paper, we have formulated the exact solutions of the non-static anisotropic gravitating source in $f(R,T)$ gravity which may lead to expansion and collapse. By assuming the no thermal conduction in gravitating source, we have determine parametric solutions in $f(R,T)$ gravity with non-static spherical geometry filled with anisotropic fluid. We have examined the range of parameter for which expansion scalar become negative and positive leading to collapse and expansion, respectively. Further, using the definition of mass function the condition for the trapped surface have been explored and it has been investigated there exists a single horizon in this case. The impact of coupling parameter $\lambda$ has been discussed in detail in both cases. For the various values of coupling parameter $\lambda$, we have plotted energy density, anisotropic pressure and anisotropic parameter in case of collapse and expansion. The physical significance of the graphs has been explained in detail.

[{'version': 'v1', 'created': 'Sat, 24 Jun 2017 08:15:28 GMT'}]

2017-08-02

[array(['Abbas', 'G.', ''], dtype=object) array(['Ahmed', 'Riaz', ''], dtype=object)]

2105.12931

Weijun Tan

Delong Qi, Weijun Tan, Qi Yao, Jingfeng Liu

YOLO5Face: Why Reinventing a Face Detector

cs.CV

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

Tremendous progress has been made on face detection in recent years using convolutional neural networks. While many face detectors use designs designated for detecting faces, we treat face detection as a generic object detection task. We implement a face detector based on the YOLOv5 object detector and call it YOLO5Face. We make a few key modifications to the YOLOv5 and optimize it for face detection. These modifications include adding a five-point landmark regression head, using a stem block at the input of the backbone, using smaller-size kernels in the SPP, and adding a P6 output in the PAN block. We design detectors of different model sizes, from an extra-large model to achieve the best performance to a super small model for real-time detection on an embedded or mobile device. Experiment results on the WiderFace dataset show that on VGA images, our face detectors can achieve state-of-the-art performance in almost all the Easy, Medium, and Hard subsets, exceeding the more complex designated face detectors. The code is available at \url{https://github.com/deepcam-cn/yolov5-face}

[{'version': 'v1', 'created': 'Thu, 27 May 2021 03:54:38 GMT'} {'version': 'v2', 'created': 'Thu, 2 Dec 2021 04:40:13 GMT'} {'version': 'v3', 'created': 'Thu, 27 Jan 2022 16:26:17 GMT'}]

2022-01-28

[array(['Qi', 'Delong', ''], dtype=object) array(['Tan', 'Weijun', ''], dtype=object) array(['Yao', 'Qi', ''], dtype=object) array(['Liu', 'Jingfeng', ''], dtype=object)]

2007.08894

Henry Ki{\ss}ler

Henry Ki{\ss}ler

Off-shell Diagrammatics for Quantum Gravity

Phys. Lett. B 816 (2021) 136219

10.1016/j.physletb.2021.136219

hep-th gr-qc

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

This article reports on how diagrammatic identities of Yang--Mills theory translate to diagrammatics for pure gravity. For this, we consider the Einstein--Hilbert action and follow the approach of Capper, Leibbrandt, and Medrano and expand the inverse metric density around the Minkowski metric. By analogy to Yang--Mills theory, cancellation identities are constructed for the graviton as well as the ghost vertices up to the valency of six.

[{'version': 'v1', 'created': 'Fri, 17 Jul 2020 10:51:30 GMT'} {'version': 'v2', 'created': 'Wed, 24 Mar 2021 15:38:19 GMT'}]

2021-03-25

[array(['Kißler', 'Henry', ''], dtype=object)]

1704.04449

Jennifer Wilson

Jeremy Miller, Peter Patzt, and Jennifer C. H. Wilson

Central stability for the homology of congruence subgroups and the second homology of Torelli groups

Corrections and substantial revisions. 36 pages, 1 figure. To appear in Advances in Mathematics

Adv. Math. 354 (2019), 106740, 45 pp

10.1016/j.aim.2019.106740

math.AT math.GR math.GT math.RT

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

We prove a representation stability result for the second homology groups of Torelli subgroups of mapping class groups and automorphism groups of free groups. This strengthens the results of Boldsen-Hauge Dollerup and Day-Putman. We also prove a new representation stability result for the homology of certain congruence subgroups, partially improving upon the work of Putman-Sam. These results follow from a general theorem on syzygies of certain modules with finite polynomial degree.

[{'version': 'v1', 'created': 'Fri, 14 Apr 2017 15:14:27 GMT'} {'version': 'v2', 'created': 'Mon, 22 Jul 2019 16:58:13 GMT'}]

2020-09-28

[array(['Miller', 'Jeremy', ''], dtype=object) array(['Patzt', 'Peter', ''], dtype=object) array(['Wilson', 'Jennifer C. H.', ''], dtype=object)]

2206.12989

David Eppstein

David Eppstein

Locked and unlocked smooth embeddings of surfaces

8 pages, 8 figures. To appear in 34th Canadian Conference on Computational Geometry

cs.CG math.MG

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

We study the continuous motion of smooth isometric embeddings of a planar surface in three-dimensional Euclidean space, and two related discrete analogues of these embeddings, polygonal embeddings and flat foldings without interior vertices, under continuous changes of the embedding or folding. We show that every star-shaped or spiral-shaped domain is unlocked: a continuous motion unfolds it to a flat embedding. However, disks with two holes can have locked embeddings that are topologically equivalent to a flat embedding but cannot reach a flat embedding by continuous motion.

[{'version': 'v1', 'created': 'Sun, 26 Jun 2022 22:57:15 GMT'}]

2022-06-28

[array(['Eppstein', 'David', ''], dtype=object)]

1903.09344

Weihuang Xu

Weihuang Xu, Guohao Yu, Alina Zare, Brendan Zurweller, Diane Rowland, Joel Reyes-Cabrera, Felix B Fritschi, Roser Matamala, Thomas E. Juenger

Overcoming Small Minirhizotron Datasets Using Transfer Learning

Computers and Electronics in Agriculture, 175 (2020)

10.1016/j.compag.2020.105466

cs.CV

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

Minirhizotron technology is widely used for studying the development of roots. Such systems collect visible-wavelength color imagery of plant roots in-situ by scanning an imaging system within a clear tube driven into the soil. Automated analysis of root systems could facilitate new scientific discoveries that would be critical to address the world's pressing food, resource, and climate issues. A key component of automated analysis of plant roots from imagery is the automated pixel-level segmentation of roots from their surrounding soil. Supervised learning techniques appear to be an appropriate tool for the challenge due to varying local soil and root conditions, however, lack of enough annotated training data is a major limitation due to the error-prone and time-consuming manually labeling process. In this paper, we investigate the use of deep neural networks based on the U-net architecture for automated, precise pixel-wise root segmentation in minirhizotron imagery. We compiled two minirhizotron image datasets to accomplish this study: one with 17,550 peanut root images and another with 28 switchgrass root images. Both datasets were paired with manually labeled ground truth masks. We trained three neural networks with different architectures on the larger peanut root dataset to explore the effect of the neural network depth on segmentation performance. To tackle the more limited switchgrass root dataset, we showed that models initialized with features pre-trained on the peanut dataset and then fine-tuned on the switchgrass dataset can improve segmentation performance significantly. We obtained 99\% segmentation accuracy in switchgrass imagery using only 21 training images. We also observed that features pre-trained on a closely related but relatively moderate size dataset like our peanut dataset are more effective than features pre-trained on the large but unrelated ImageNet dataset.

[{'version': 'v1', 'created': 'Fri, 22 Mar 2019 03:40:25 GMT'} {'version': 'v2', 'created': 'Mon, 26 Aug 2019 17:53:20 GMT'} {'version': 'v3', 'created': 'Fri, 24 Apr 2020 15:13:48 GMT'}]

2020-07-02

[array(['Xu', 'Weihuang', ''], dtype=object) array(['Yu', 'Guohao', ''], dtype=object) array(['Zare', 'Alina', ''], dtype=object) array(['Zurweller', 'Brendan', ''], dtype=object) array(['Rowland', 'Diane', ''], dtype=object) array(['Reyes-Cabrera', 'Joel', ''], dtype=object) array(['Fritschi', 'Felix B', ''], dtype=object) array(['Matamala', 'Roser', ''], dtype=object) array(['Juenger', 'Thomas E.', ''], dtype=object)]

astro-ph/9904257

Stephan Wellstein

N. Langer (1), A. Heger (2), S. Wellstein (1) and F. Herwig (1) ((1) Institut fuer Physik, Universitaet Potsdam, Germany (2) Astronomy and Astrophysics Department, University of California, Santa Cruz)

Mixing and nucleosynthesis in rotating TP-AGB stars

4 pages, 7 figures, final accepted version, only minor changes to previous version

astro-ph

We present the first evolutionary models of intermediate mass stars up to their thermal pulses which include effects of rotation on the stellar structure as well as rotationally induced mixing of chemical species and angular momentum. We find a significant angular momentum transport from the core to the hydrogen-rich envelope and obtain a white dwarf rotation rate comparable to current observational upper limits of 50 km/s. Large angular momentum gradients at the bottom of the convective envelope and the tip of the pulse driven convective shell are shown to produce marked chemical mixing between the proton-rich and the 12C-rich layers during the so called third dredge-up. This leads to a subsequent production of 13C which is followed by neutron production through 13C(alpha,n) in radiative layers in between thermal pulses. Although uncertainties in the efficiency of rotational mixing processes persist, we conclude that rotation is capable of producing a 13C-rich layer as required for the occurrence of the s-process in TP-AGB stars.

[{'version': 'v1', 'created': 'Tue, 20 Apr 1999 08:53:45 GMT'} {'version': 'v2', 'created': 'Tue, 11 May 1999 14:55:51 GMT'}]

2007-05-23

[array(['Langer', 'N.', ''], dtype=object) array(['Heger', 'A.', ''], dtype=object) array(['Wellstein', 'S.', ''], dtype=object) array(['Herwig', 'F.', ''], dtype=object)]

1507.00719

Jason Miller

Jason Miller and Scott Sheffield

Liouville quantum gravity and the Brownian map I: The QLE(8/3,0) metric

73 pages, 14 figures

math.PR math-ph math.CV math.MP

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

Liouville quantum gravity (LQG) and the Brownian map (TBM) are two distinct models of measure-endowed random surfaces. LQG is defined in terms of a real parameter $\gamma$, and it has long been believed that when $\gamma = \sqrt{8/3}$, the LQG sphere should be equivalent (in some sense) to TBM. However, the LQG sphere comes equipped with a conformal structure, and TBM comes equipped with a metric space structure, and endowing either one with the other's structure has been an open problem for some time. This paper is the first in a three-part series that unifies LQG and TBM by endowing each object with the other's structure and showing that the resulting laws agree. The present work uses a form of the quantum Loewner evolution (QLE) to construct a metric on a dense subset of a $\sqrt{8/3}$-LQG sphere and to establish certain facts about the law of this metric, which are in agreement with similar facts known for TBM. The subsequent papers will show that this metric extends uniquely and continuously to the entire $\sqrt{8/3}$-LQG surface and that the resulting measure-endowed metric space is TBM.

[{'version': 'v1', 'created': 'Thu, 2 Jul 2015 19:54:32 GMT'} {'version': 'v2', 'created': 'Sat, 27 Feb 2016 11:23:24 GMT'} {'version': 'v3', 'created': 'Mon, 29 Jul 2019 12:58:43 GMT'}]

2019-07-30

[array(['Miller', 'Jason', ''], dtype=object) array(['Sheffield', 'Scott', ''], dtype=object)]

2010.00457

Kartick Chandra Sarkar

Kartick Chandra Sarkar, Amiel Sternberg and Orly Gnat

A new ionisation network and radiation transport module in PLUTO

19 pages, accepted by MNRAS. Added error estimates for radiative transfer, and runtime plots for different components of the code. Added late time (>1Myr) dynamics of the HII region

10.1093/mnras/stab578

astro-ph.GA astro-ph.IM

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

We introduce a new general-purpose time-dependent ionisation network (IN) and a radiation transport (RT) module in the magneto-hydrodynamic (MHD) code PLUTO. Our ionisation network is reliable for temperatures ranging from 5e3 to 3e8 K, and includes all ionisation states of H, He, C, N, O, Ne, Mg, Si, S and Fe making it suitable for studying a variety of astrophysical scenarios. Radiation loss for each ion-electron pair is calculated using CLOUDY-17 data on-the-fly. Photo-ionisation and charge exchange are the chemical heating mechanisms. The IN is fully coupled to the radiation transport module over a very large range of opacities at different frequencies. The RT module employs a method of short characteristics assuming spherical symmetry. The radiation module requires the assumption of spherical symmetry, while the IN is compatible with full 3D. We also include a simple prescription for dust opacity, grain destruction, and the dust contribution to radiation pressure. We present numerical tests to show the reliability and limitations of the new modules. We also present a post-processing tool to calculate projected column densities and emission spectra.

[{'version': 'v1', 'created': 'Thu, 1 Oct 2020 14:51:35 GMT'} {'version': 'v2', 'created': 'Mon, 1 Mar 2021 19:01:07 GMT'}]

2021-03-17

[array(['Sarkar', 'Kartick Chandra', ''], dtype=object) array(['Sternberg', 'Amiel', ''], dtype=object) array(['Gnat', 'Orly', ''], dtype=object)]

1609.03383

Andreas Michels

Andreas Michels, Raoul Weber, Ivan Titov, Denis Mettus, \'Elio Alberto P\'erigo, Inma Peral, Oriol Vallcorba, Joachim Kohlbrecher, Kiyonori Suzuki, Masaaki Ito, Akira Kato, and Masao Yano

Spin structures of textured and isotropic Nd-Fe-B-based nanocomposites: Evidence for correlated crystallographic and spin texture

Phys. Rev. Applied 7, 024009 (2017)

10.1103/PhysRevApplied.7.024009

cond-mat.mes-hall

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

We report the results of a comparative study of the magnetic microstructure of textured and isotropic $\mathrm{Nd}_2\mathrm{Fe}_{14}\mathrm{B}/\alpha$-$\mathrm{Fe}$ nanocomposites using magnetometry, transmission electron microscopy, synchrotron x-ray diffraction, and, in particular, magnetic small-angle neutron scattering (SANS). Analysis of the magnetic neutron data of the textured specimen and computation of the correlation function of the spin misalignment SANS cross section suggests the existence of inhomogeneously magnetized regions on an intraparticle nanometer length scale, about $40-50 \, \mathrm{nm}$ in the remanent state. Possible origins for this spin disorder are discussed: it may originate in thin grain-boundary layers (where the materials parameters are different than in the $\mathrm{Nd}_2\mathrm{Fe}_{14}\mathrm{B}$ grains), or it may reflect the presence of crystal defects (introduced via hot pressing), or the dispersion in the orientation distribution of the magnetocrystalline anisotropy axes of the $\mathrm{Nd}_2\mathrm{Fe}_{14}\mathrm{B}$ grains. X-ray powder diffraction data reveal a crystallographic texture in the direction perpendicular to the pressing direction -- a finding which might be related to the presence of a texture in the magnetization distribution, as inferred from the magnetic SANS data.

[{'version': 'v1', 'created': 'Mon, 12 Sep 2016 13:16:05 GMT'}]

2017-02-15

[array(['Michels', 'Andreas', ''], dtype=object) array(['Weber', 'Raoul', ''], dtype=object) array(['Titov', 'Ivan', ''], dtype=object) array(['Mettus', 'Denis', ''], dtype=object) array(['Périgo', 'Élio Alberto', ''], dtype=object) array(['Peral', 'Inma', ''], dtype=object) array(['Vallcorba', 'Oriol', ''], dtype=object) array(['Kohlbrecher', 'Joachim', ''], dtype=object) array(['Suzuki', 'Kiyonori', ''], dtype=object) array(['Ito', 'Masaaki', ''], dtype=object) array(['Kato', 'Akira', ''], dtype=object) array(['Yano', 'Masao', ''], dtype=object)]