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Penalized Clustering of Large Scale Functional Data with Multiple Covariates ; In this article, we propose a penalized clustering method for large scale data with multiple covariates through a functional data approach. In the proposed method, responses and covariates are linked together through nonparametric multivariate functions fixed effects, which have great flexibility in modeling a variety of function features, such as jump points, branching, and periodicity. Functional ANOVA is employed to further decompose multivariate functions in a reproducing kernel Hilbert space and provide associated notions of main effect and interaction. Parsimonious random effects are used to capture various correlation structures. The mixedeffect models are nested under a general mixture model, in which the heterogeneity of functional data is characterized. We propose a penalized Henderson's likelihood approach for modelfitting and design a rejectioncontrolled EM algorithm for the estimation. Our method selects smoothing parameters through generalized crossvalidation. Furthermore, the Bayesian confidence intervals are used to measure the clustering uncertainty. Simulation studies and realdata examples are presented to investigate the empirical performance of the proposed method. Opensource code is available in the R package MFDA.

A generalized CahnHilliard equation for biological applications ; Recently we considered a stochastic discrete model which describes fronts of cells invading a wound citeKSS. In the model cells can move, proliferate, and experience cellcell adhesion. In this work we focus on a continuum description of this phenomenon by means of a generalized CahnHilliard equation GCH with a proliferation term. As in the discrete model, there are two interesting regimes. For subcritical adhesion, there are propagating pulled fronts, similarly to those of FisherKolmogorov equation. The problem of front velocity selection is examined, and our theoretical predictions are in a good agreement with a numerical solution of the GCH equation. For supercritical adhesion, there is a nontrivial transient behavior, where density profile exhibits a secondary peak. To analyze this regime, we investigated relaxation dynamics for the CahnHilliard equation without proliferation. We found that the relaxation process exhibits selfsimilar behavior. The results of continuum and discrete models are in a good agreement with each other for the different regimes we analyzed.

A Natural Supersymmetric Model with MeV Dark Matter ; It has previously been proposed that annihilating dark matter particles with MeVscale masses could be responsible for the flux of 511 keV photons observed from the region of the Galactic Bulge. The conventional wisdom, however, is that it is very challenging to construct a viable particle physics model containing MeV dark matter. In this letter, we challenge this conclusion by describing a simple and natural supersymmetric model in which the lightest supersymmetric particle naturally has a MeVscale mass and the other phenomenological properties required to generate the 511 keV emission. In particular, the small sim 105 effective couplings between dark matter and the Standard Model fermions required in this scenario naturally lead to radiative corrections that generate MeVscale masses for both the dark matter candidate and the mediator particle.

Temporal Correlations of Local Network Losses ; We introduce a continuum model describing data losses in a single node of a packetswitched network like the Internet which preserves the discrete nature of the data loss process. em By construction, the model has critical behavior with a sharp transition from exponentially small to finite losses with increasing data arrival rate. We show that such a model exhibits strong fluctuations in the loss rate at the critical point and nonMarkovian powerlaw correlations in time, in spite of the Markovian character of the data arrival process. The continuum model allows for rather general incoming data packet distributions and can be naturally generalized to consider the buffer server idleness statistics.

A Unified Model of Phantom Energy and Dark Matter ; To explain the acceleration of the cosmological expansion researchers have considered an unusual form of massenergy generically called dark energy. Dark energy has a ratio of pressure over mass density which obeys wprho 13. This form of massenergy leads to accelerated expansion. An extreme form of dark energy, called phantom energy, has been proposed which has wprho 1. This possibility is favored by the observational data. The simplest model for phantom energy involves the introduction of a scalar field with a negative kinetic energy term. Here we show that theories based on graded Lie algebras naturally have such a negative kinetic energy and thus give a model for phantom energy in a less ad hoc manner. We find that the model also contains ordinary scalar fields and anticommuting Grassmann vector fields which act as a form of two component dark matter. Thus from a gauge theory based on a graded algebra we naturally obtained both phantom energy and dark matter.

Multivariate stochastic volatility using state space models ; A Bayesian procedure is developed for multivariate stochastic volatility, using state space models. An autoregressive model for the logreturns is employed. We generalize the inverted Wishart distribution to allow for different correlation structure between the observation and state innovation vectors and we extend the convolution between the Wishart and the multivariate singular beta distribution. A multiplicative model based on the generalized inverted Wishart and multivariate singular beta distributions is proposed for the evolution of the volatility and a flexible sequential volatility updating is employed. The proposed algorithm for the volatility is fast and computationally cheap and it can be used for online forecasting. The methods are illustrated with an example consisting of foreign exchange rates data of 8 currencies. The empirical results suggest that timevarying correlations can be estimated efficiently, even in situations of high dimensional data.

Dark Interactions and Cosmological FineTuning ; Cosmological models involving an interaction between dark matter and dark energy have been proposed in order to solve the socalled coincidence problem. Different forms of coupling have been studied, but there have been claims that observational data seem to narrow some of them down to something annoyingly close to the LambdaCDM model, thus greatly reducing their ability to deal with the problem in the first place. The smallness problem of the initial energy density of dark energy has also been a target of cosmological models in recent years. Making use of a moderately general coupling scheme, this paper aims to unite these different approaches and shed some light as to whether this class of models has any true perspective in suppressing the aforementioned issues that plague our current understanding of the universe, in a quantitative and unambiguous way.

Testing polynomial covariate effects in linear and generalized linear mixed models ; An important feature of linear mixed models and generalized linear mixed models is that the conditional mean of the response given the random effects, after transformed by a link function, is linearly related to the fixed covariate effects and random effects. Therefore, it is of practical importance to test the adequacy of this assumption, particularly the assumption of linear covariate effects. In this paper, we review procedures that can be used for testing polynomial covariate effects in these popular models. Specifically, four types of hypothesis testing approaches are reviewed, i.e. R tests, likelihood ratio tests, score tests and residualbased tests. Derivation and performance of each testing procedure will be discussed, including a small simulation study for comparing the likelihood ratio tests with the score tests.

General twoorderparameter GinzburgLandau model with quadratic and quartic interactions ; GinzburgLandau model with two order parameters appears in many condensedmatter problems. However, even for scalar order parameters, the most general U1symmetric Landau potential with all quadratic and quartic terms contains 13 independent coefficients and cannot be minimized with straightforward algebra. Here, we develop a geometric approach that circumvents this computational difficulty and allows one to study properties of the model without knowing the exact position of the minimum. In particular, we find the number of minima of the potential, classify explicit symmetries possible in this model, establish conditions when and how these symmetries are spontaneously broken, and explicitly describe the phase diagram.

Feynman diagrams and minimal models for operadic algebras ; We construct an explicit minimal model for an algebra over the cobarconstruction of a differential graded operad. The structure maps of this minimal model are expressed in terms of sums over decorated trees. We introduce the appropriate notion of a homotopy equivalence of operadic algebras and show that our minimal model is homotopy equivalent to the original algebra. All this generalizes and gives a conceptual explanation of wellknown results for Ainfinity algebras. Further, we show that these results carry over to the case of algebras over modular operads; the sums over trees get replaced by sums over general Feynman graphs. As a byproduct of our work we prove gaugeindependence of Kontsevich's dual construction' producing graph cohomology classes from contractible differential graded Frobenius algebras.

Growth Index of DGP Model and Current Growth Rate Data ; Recently, some efforts focus on differentiating dark energy and modified gravity with the growth function deltaz. In the literature, it is useful to parameterize the growth rate fequiv dlndeltadln aOmegamgamma with the growth index gamma. In this note, we consider the general DGP model with any Omegak. We confront the growth index of DGP model with currently available growth rate data and find that the DGP model is still consistent with it. This implies that more and better growth rate data are required to distinguish between dark energy and modified gravity.

Nonlocal operator basis from the path representation of the Mk1,k2 and the Mk1,2k3 minimal models ; We reinterpret a path describing a state in an irreducible module of the unitary minimal model Mk1,k2 in terms of a string of charged operators acting on the module's groundstate path. Each such operator acts nonlocally on a path. The path characteristics are then translated into a set of conditions on sequences of operators that provide an operator basis. As an application, we rederive the vacuum finite fermionic character by constructing the generating function of these basis states. These results generalize directly to the Mk1,2k3 models, the close relatives of the unitary models in terms of path description.

On the energy of homogeneous cosmologies ; An energy for the homogeneous cosmological models is presented. More specifically, using an appropriate natural prescription, we find the energy within any region with any gravitational source for a large class of gravity theoriesnamely those with a tetrad descriptionfor all 9 Bianchi types. Our energy is given by the value of the Hamiltonian with homogeneous boundary conditions; this value vanishes for all regions in all Bianchi class A models, and it does not vanish for any class B model. This is so not only for Einstein's general relativity but, moreover, for the whole 3parameter class of tetradteleparallel theories. For the physically favored one parameter subclass, which includes the teleparallel equivalent of Einstein's theory as an important special case, the energy for all class B models is, contrary to expectation, negative.

On population extinction risk in the aftermath of a catastrophic event ; We investigate how a catastrophic event modeled as a temporary fall of the reproduction rate increases the extinction probability of an isolated selfregulated stochastic population. Using a variant of the Verhulst logistic model as an example, we combine the probability generating function technique with an eikonal approximation to evaluate the exponentially large increase in the extinction probability caused by the catastrophe. This quantity is given by the eikonal action computed over the optimal path instanton of an effective classical Hamiltonian system with a timedependent Hamiltonian. For a general catastrophe the eikonal equations can be solved numerically. For simple models of catastrophic events analytic solutions can be obtained. One such solution becomes quite simple close to the bifurcation point of the Verhulst model. The eikonal results for the increase in the extinction probability caused by a catastrophe agree well with numerical solutions of the master equation.

Polling systems with parameter regeneration, the general case ; We consider a polling model with multiple stations, each with Poisson arrivals and a queue of infinite capacity. The service regime is exhaustive and there is Jacksonian feedback of served customers. What is new here is that when the server comes to a station it chooses the service rate and the feedback parameters at random; these remain valid during the whole stay of the server at that station. We give criteria for recurrence, transience and existence of the sth moment of the return time to the empty state for this model. This paper generalizes the model, when only two stations accept arriving jobs, which was considered in Ann. Appl. Probab. 17 2007 14471473. Our results are stated in terms of Lyapunov exponents for random matrices. From the recurrence criteria it can be seen that the polling model with parameter regeneration can exhibit the unusual phenomenon of null recurrence over a thick region of parameter space.

Optical Sum Rule in Strongly Correlated Systems ; We discuss the problem of a possible violation of the optical sum rule in the normal non superconducting state of strongly correlated electronic systems, using our recently proposed DMFTSigma approach, applied to two typical models the hot spot model of the pseudogap state and disordered Anderson Hubbard model. We explicitly demonstrate that the general Kubo single band sum rule is satisfied for both models. However, the optical integral itself is in general dependent on temperature and characteristic parameters, such as pseudogap width, correlation strength and disorder scattering, leading to effective violation of the optical sum rule, which may be observed in the experiments.

CP asymmetries of B to phi KS and B to eta' KS in SUSY GUT Model with Nonuniversal Sfermion Masses ; We analyze CP asymmetries of B to phi KS and B to eta' KS in a supersymmetric grand unified theory in which only the third generation sfermions contained in 10Q, Uc, Ec of SU5 can have a different mass from the others. One of the advantages of this nonuniversal mass model is that the first two generation sfermion masses can be large whereas both left and right handed stops are light so as to stabilize the weak scale. Therefore, we studied a minimal supersymmetric standard model parameter region in which a fine tuning in Higgs sector is relaxed owing to light masses of stops, gluino and higgsinos. In such a parameter region, the chargino contribution is as important as the gluino one. We show that the CP asymmetries of B to phi KS and B to eta' KS can deviate from their standard model predicted values by O0.1 because of constructive interference between gluino and chargino contributions.

Generalized parton distributions of the pion ; Generalized Parton Distributions of the pion are evaluated in chiral quark models with the help of double distributions. As a result the polynomiality conditions are automatically satisfied. In addition, positivity constraints, proper normalization and support, sum rules, and soft pion theorems are fulfilled. We obtain explicit expressions holding at the lowenergy quarkmodel scale, which exhibit no factorization in the tdependence. The crucial QCD evolution of the quarkmodel distributions is carried out up to experimental or lattice scales. The obtained results for the Parton Distribution Function and the Parton Distribution Amplitude describe the available experimental and lattice data, confirming that the quarkmodel scale is low, around 320 MeV.

A Littelmann path model for crystals of Generalized KacMoody algebras revisited ; A Littelmann path model is constructed for crystals pertaining to a not necessarily symmetrizable BorcherdsCartan matrix. Here one must overcome several combinatorial problems coming from the imaginary simple roots. The main results are an isomorphism theorem and a character formula of BorcherdsKacWeyl type for the crystals. In the symmetrizable case, the isomorphism theorem implies that the crystals constructed by this path model coincide with those of Jeong, Kang, Kashiwara and Shin obtained by taking the limit at q0 in the quantized enveloping algebra.

Some Issues in a Gauge Model of Unparticles ; We address in a recent gauge model of unparticles the issues that are important for consistency of a gauge theory, i.e., unitarity and Ward identity of physical amplitudes. We find that nonintegrable singularities arise in physical quantities like cross section and decay rate from gauge interactions of unparticles. We also show that Ward identity is violated due to the lack of a dispersion relation for charged unparticles although the WardTakahashi identity for general Green functions is incorporated in the model. A previous observation that the unparticle's with scaling dimension d contribution to the gauge boson selfenergy is a factor 2d of the particle's has been extended to the Green function of triple gauge bosons. This 2d rule may be generally true for any point Green functions of gauge bosons. This implies that the model would be trivial even as one that mimics certain dynamical effects on gauge bosons in which unparticles serve as an interpolating field.

Phase Transitions, Chaos and Joint Action in the Life Space Foam ; This paper extends our recently developed Life Space Foam LSF model of motivated cognitive dynamics citeIA. LSF uses adaptive path integrals to generate Lewinian forcefields on smooth manifolds, in order to characterize the dynamics of individual goaldirected action. According to explanatory theories growing in acceptance in cognitive neuroscience, one of the key properties of this dynamics, capable of linking it to microscopiclevel cortical neurodynamics, is its metastability and the resulting phase transitions. Our extended LSF model incorporates the notion of phase transitions and complements it with embedded geometrical chaos. To describe this LSF phase transition, a general pathintegral is used, along the corresponding LSF topology change. As a result, our extended LSF model is able to rigorously represent coaction by two or more actors in the common LSFmanifold. The model yields substantial qualitative differences in geometrical properties between bilateral and multilateral coaction due to intrinsic chaotic coupling between n actors when ngeq 3. Keywords cognitive dynamics, adaptive path integrals, phase transitions, chaos, topology change, human joint action, function approximation

ThirdOrder Density Perturbation and OneLoop Power Spectrum in DarkEnergyDominated Universe ; We investigate the thirdorder density perturbation and the oneloop correction to the linear power spectrum in the darkenergy cosmological model. Our main interest is to understand the darkenergy effect on baryon acoustic oscillations in a quasinonlinear regime k approx 0.1hMpc. Analytical solutions and simple fitting formulae are presented for the darkenergy model with the general timevarying equation of state wa. It turns out that the power spectrum coincides with the approximate result based on the EdS Einstein deSitter model within 1 for k0.4hMpc at z0 in the WMAP Wilkinson Microwave Anisotropy Probe 5yr bestfitting cosmological model, which suggests that the cosmological dependence is very small.

Leptogenesis in the extension of the ZeeBabu model ; We demonstrate that the extension of the ZeeBabu model can generate not only the small neutrino masses but also the baryon number asymmetry in the universe. In particular, we show that the scale of the singlet scalar responsible for the leptogenesis can be of order 1 TeV, that can be tested at the LHC and ILC. We also considered the possible minimal extension of this model to generate the dark matter.

The Ups and Downs of Modeling Financial Time Series with Wiener Process Mixtures ; Starting from inhomogeneous time scaling and linear decorrelation between successive price returns, Baldovin and Stella recently proposed a way to build a model describing the time evolution of a financial index. We first make it fully explicit by using Student distributions instead of power lawtruncated L'evy distributions; we also show that the analytic tractability of the model extends to the larger class of symmetric generalized hyperbolic distributions and provide a full computation of their multivariate characteristic functions; more generally, the stochastic processes arising in this framework are representable as mixtures of Wiener processes. The Baldovin and Stella model, while mimicking well volatility relaxation phenomena such as the Omori law, fails to reproduce other stylized facts such as the leverage effect or some time reversal asymmetries. We discuss how to modify the dynamics of this process in order to reproduce real data more accurately.

LRS Bianchi Type I Models with Anisotropic Dark Energy and Constant Deceleration Parameter ; Locally rotationally symmetric LRS Bianchi Type I cosmological models are examined in the presence of dynamically anisotropic dark energy and perfect fluid. We assume that the dark energy DE is minimally interacting, has dynamical energy density, anisotropic equation of state parameter EoS. The conservation of the energymomentum tensor of the DE is assumed to consist of two separately additive conserved parts. A special law is assumed for the deviation from isotropic EoS, which is consistent with the assumption on the conservation of the energymomentum tensor of the DE. Exact solutions of Einstein's field equations are obtained by assuming a special law of variation for the mean Hubble parameter, which yields a constant value of the deceleration parameter. Geometrical and kinematic properties of the models and the behaviour of the anisotropy of the dark energy has been carried out. The models give dynamically anisotropic expansion history for the universe that allows to fine tune the isotropization of the Bianchi metric, hence the CMB anisotropy.

Generalized parton distributions of pseudoscalar mesons in a covariant constituent quark model ; The isoscalar twisttwo generalized parton distributions GPDs of the pion and the kaon are calculated in a Poincare covariant BetheSalpeter constituent quark model. Results are presented for several values of the parameters xi and t. The results satisfy the form factor constraints and the polynomiality condition. For the pion GPD, also the isospin symmetry constraint is fulfilled. The influence of kinematical variables and model parameters on the support of the GPDs is investigated. To this end, the strength parameters and quark masses of the constituent quark model are artificially varied.

A Model Of Inflationary Cosmology Without Singularity ; In this letter, we propose a model of inflationary cosmology with a bounce preceded and study its primordial curvature perturbations. Our model gives rise to a primordial power spectrum with a feature of oscillation on large scales compared with the nearly scaleinvariant spectrum generated by the traditional slow rolling inflation model. We will show this effect changes the Cosmic Microwave Background CMB temperature power spectrum and the Large Scale Structure LSS matter power spectrum. And further with a detailed simulation we will point out this signal is detectable to the forthcoming observations, such as PLANCK and LAMOST.

An Abundance of Heterotic Vacua ; We explicitly construct the largest dataset to date of heterotic vacua arising from stable vector bundles on CalabiYau threefolds. Focusing on elliptically fibered CalabiYau manifolds with spectral cover bundles, we show that the number of heterotic models with nonzero number of generations is finite. We classify these models according to the complex base of their CalabiYau threefold and to the unification gauge group that they preserve in four dimensions. This database of the order of 107 models, which includes potential Standard Model candidates, is subjected to some preliminary statistical analyses. The additional constraint that there should be three net generations of particles gives a dramatic reduction of the number of vacua.

Statistical thermodynamics of a two dimensional relativistic gas ; In this article we study a fully relativistic model of a two dimensional harddisk gas. This model avoids the general problems associated with relativistic particle collisions and is therefore an ideal system to study relativistic effects in statistical thermodynamics. We study this model using moleculardynamics simulation, concentrating on the velocity distribution functions. We obtain results for x and y components of velocity in the rest frame Gamma as well as the moving frame Gamma'. Our results confirm that Juttner distribution is the correct generalization of MaxwellBoltzmann distribution. We obtain the same temperature parameter beta for both frames consistent with a recent study of a limited onedimensional model. We also address the controversial topic of temperature transformation. We show that while local thermal equilibrium holds in the moving frame, relying on statistical methods such as distribution functions or equipartition theorem are ultimately inconclusive in deciding on a correct temperature transformation law if any.

Bifurcationbased parameter tuning in a model of the GnRH pulse and surge generator ; We investigate a model of the GnRH pulse and surge generator, with the definite aim of constraining the model GnRH output with respect to a physiologically relevant list of specifications. The alternating pulse and surge pattern of secretion results from the interaction between a GnRH secreting system and a regulating system exhibiting fastslow dynamics. The mechanisms underlying the behavior of the model are reminded from the study of the BoundaryLayer System according to the dissection method principle. Using singular perturbation theory, we describe the sequence of bifurcations undergone by the regulating FitzHughNagumo system, encompassing the rarely investigated case of homoclinic connexion. Basing on pure dynamical considerations, we restrict the space of parameter search for the regulating system and describe a foliation of this restricted space, whose leaves define constant duration ratios between the surge and the pulsatility phase in the whole system. We propose an algorithm to fix the parameter values to also meet the other prescribed ratios dealing with amplitude and frequency features of the secretion signal. We finally apply these results to illustrate the dynamics of GnRH secretion in the ovine species and the rhesus monkey.

Decay of Entanglement for SolidState Qubits ; We investigate the time evolution of entanglement under various models of decoherence A general heuristic model based on local relaxation and dephasing times, and two microscopic models describing decoherence of electron spin qubits in quantum dots due to the hyperfine interaction with the nuclei. For each of the decoherence models, we investigate and compare how long the entanglement can be detected. We also introduce filtered witness operators, which extend the available detection time, and investigate this detection time for various multipartite entangled states. By comparing the time required for detection with the time required for generation and manipulation of entanglement, we estimate for a range of different entangled states how many qubits can be entangled in a onedimensional array of electron spin qubits.

A model for the evolutionary diversification of religions ; We address the problem of diversification in religions by studying selection on cultural memes that colonize humans hosts. In analogy to studying the evolution of pathogens or symbionts colonizing animal hosts, we use models for hostpathogen dynamics known from theoretical epidemiology. In these models, religious memes colonize individual humans. Rates of transmission of memes between humans, i.e., transmission of cultural content, and rates of loss of memes loss of faith are determined by the phenotype of the cultural memes, and by interactions between hosts carrying different memes. In particular, based on the notion that religion can lead to oppression of lower classes once a religious society has reached a certain size, we assume that the rate of loss increases as the number of humans colonized by a particular meme phenotype increases. This generates frequencydependent selection on cultural memes, and we use evolutionary theory to show that this frequency dependence can generate the emergence of coexisting clusters of different meme types. The different clusters correspond to different religions, and hence our model describes the emergence of distinct descendent religions from single ancestral religions.

Coherent spin rotation in the presence of a phononbottleneck effect ; A characteristic of spin reversal in the presence of phononbottleneck is the deviation of the magnetization cycle from a reversible function into an opened hysterezis cycle. In recent experiments on molecular magnets e.g. V15 and Ru2, the zerofield level repulsion was sufficiently large to ensure an otherwise adiabatic passage through zerofield and the magnetization curves can be described by using only a phononbottleneck model. Here, we generalize the phononbottleneck model into a model able to blend the nonadiabatic dynamics of spins with the presence of a nonequilibrium phonon bath. In this simple phenomenological model, Bloch equations are written in the eigenbasis of the effective spin Hamiltonian, considered to be a twolevel system at low temperatures. The relaxation term is given by the phononbottleneck mechanism. To the expense of calculus time, the method can be generalized to multilevel systems, where the notion of Bloch sphere does not apply but the density matrix formalism is still applicable.

A Causal Alternative for c0 Strings ; We review a recently discovered continuum limit for the onematrix model which describes causal twodimensional quantum gravity. The behaviour of the quantum geometry in this limit is different from the quantum geometry of Euclidean twodimensional quantum gravity defined by taking the standard continuum limit of the onematrix model. Geodesic distance and time scale with canonical dimensions in this new limit, contrary to the situation in Euclidean twodimensional quantum gravity. Remarkably, whenever we compare, the known results of generalized causal dynamical triangulations are reproduced exactly by the onematrix model. We complement previous results by giving a geometrical interpretation of the new model in terms of a generalization of the loop equation of Euclidean dynamical triangulations. In addition, we discuss the time evolution of the quantum geometry.

Reexamination of Polytropic Spheres in Palatini fR Gravity ; We investigate spherically symmetric, static matter configurations with polytropic equation of state for a class of fR models in Palatini formalism and show that the surface singularities recently reported in the literature are not physical in the case of Planck scale modified lagrangians. In such cases, they are just an artifact of the idealized equation of state used. In fact, we show that for the models fRRpmlambda R2, with lambda on the order of the Planck length squared, the presence of a single electron in the Universe would be enough to cure all stellar singularities of this type. From our analysis it also follows that the stellar structure derived from these lagrangians is virtually undistinguishable from that corresponding to General Relativity. For ultraviolet corrected models far from the Planck scale, however, the surface singularities may indeed arise in the region of validity of the polytropic equation of state. This fact can be used to place constraints on the parameters of particular models.

Constraints on generating the primordial curvature perturbation and nonGaussianity from instant preheating ; We analyse models of inflation in which isocurvature perturbations present during inflation are converted into the primordial curvature perturbation during instant preheating. This can be due to an asymmetry between the fields present either during inflation or during preheating. We consider all the constraints that the model must satisfy in order to be theoretically valid and to satisfy observations. We show that the constraints are very tight in all of the models proposed and special initial conditions are required for the models to work. In the case where the symmetry is strongly broken during inflation the nonGaussianity parameter fNL is generally large and negative.

Leptonic Z decays in the littlest Higgs model with Tparity ; The littlest Higgs model with Tparity called the LHT model predicts the existence of the Todd leptons, which can generate contributions to some leptonic processes at the oneloop level. We calculate their contributions to the leptonic Z decay processes Zto lbarl', Zto lbarl, and Zrightarro nubarnu. We find that the Todd leptons can give significant contributions to the branching ratios of these decay processes in most of the parameter space. The experimental measurement values might generate constraints on the free parameters of the LHT model.

Metabolomic and fluxbalance analysis of agerelated decline of hypoxia tolerance in Drosophila muscle tissue ; The fruit fly D. melanogaster is increasingly used as a model organism for studying acute hypoxia tolerance and for studying aging, but the interactions between these two factors are not well known. Here we show that hypoxia tolerance degrades with age in posthypoxic recovery of wholebody movement, heart rate and ATP content. We previously used 1H NMR metabolomics and a constraintbased model of ATPgenerating metabolism to discover the end products of hypoxic metabolism in flies and generate hypotheses for the biological mechanisms. We expand the reactions in the model using tissue and agespecific microarray data from the literature, and then examine metabolomic profiles of thoraxes after 4 hours at 0.5 O2 and after 5 minutes of recovery in 40 versus 3dayold flies. Model simulations were constrained to fluxes calculated from these data. Simulations suggest that the decreased ATP production during reoxygenation seen in aging flies can be attributed to reduced recovery of mitochondrial respiration pathways and concomitant overdependence on the acetate production pathway as an energy source.

Nonlinear Structure Formation, Backreaction and Weak Gravitational Fields ; There is an ongoing debate in the literature concerning the effects of averaging out inhomogeneities backreaction'' in cosmology. In particular, some simple models of structure formation studied in the literature seem to indicate that the backreaction can play a significant role at late times, and it has also been suggested that the standard perturbed FLRW framework is no longer a good approximation during structure formation, when the density contrast becomes nonlinear. In this work we use Zalaletdinov's covariant averaging scheme macroscopic gravity or MG to show that as long as the metric of the Universe can be described by the perturbed FLRW form, the corrections due to averaging remain negligibly small. Further, using a fully relativistic and reasonably generic model of pressureless spherical collapse, we show that as long as matter velocities remain small which is true in our model, the perturbed FLRW form of the metric can be explicitly recovered. Together, these results imply that the backreaction remains small even during nonlinear structure formation, and we confirm this within the toy model with a numerical calculation.

Smoothing out Negative Tension Brane ; We propose an extension of the five dimensional gravitational action with an external source in order to allow arbitrary smoothing of the negative tension brane in the RandallSundrum model. This extended action can be derived from a model with an auxiliary four form field coupled to the gravity. We point out a further generalization of our model in relation to tachyon condensation. A possible mechanism for radion stabilization in our model is also discussed.

On quantum integrability of the LandauLifshitz model ; We investigate the quantum integrability of the LandauLifshitz model and solve the longstanding problem of finding the local quantum Hamiltonian for the arbitrary nparticle sector. The particular difficulty of the LL model quantization, which arises due to the illdefined operator product, is dealt with by simultaneously regularizing the operator product, and constructing the selfadjoint extensions of a very particular structure. The diagonalizibility difficulties of the Hamiltonian of the LL model, due to the highly singular nature of the quantummechanical Hamiltonian, are also resolved in our method for the arbitrary nparticle sector. We explicitly demonstrate the consistency of our construction with the quantum inverse scattering method due to Sklyanin, and give a prescription to systematically construct the general solution, which explains and generalizes the puzzling results of Sklyanin for the particular twoparticle sector case. Moreover, we demonstrate the Smatrix factorization and show that it is a consequence of the discontinuity conditions on the functions involved in the construction of the selfadjoint extensions.

NonAbelian condensates as alternative for dark energy ; We review basic features of cosmological models with largescale classical nonAbelian YangMills YM condensates. There exists a unique SU2 YM configuration generalizable to larger gauge groups compatible with homogeneity and isotropy of the threespace which is parameterized by a single scalar field. In the past various aspects of EinsteinYangMills EYM cosmology were discussed in the context of the Early Universe. Due to conformal invariance, solvable EYM FRW models exist both on the classical and quantum levels. To develop the YM model for dark energy one has to find mechanisms of the conformal symmetry breaking. We discuss the BornInfeld generalization and some phenomenological models motivated by quantum corrections exploring possibility of transient DE and phantom regimes.

A longrange memory stochastic model of the return in financial markets ; We present a nonlinear stochastic differential equation SDE which mimics the probability density function PDF of the return and the power spectrum of the absolute return in financial markets. Absolute return as a measure of market volatility is considered in the proposed model as a longrange memory stochastic variable. The SDE is obtained from the analogy with earlier proposed model of trading activity in the financial markets and generalized within the nonextensive statistical mechanics framework. The proposed stochastic model generates time series of the return with two power law statistics, i.e., the PDF and the power spectral density, reproducing the empirical data for the one minute trading return in the NYSE.

Vortices and Superfields on a Graph ; We extend the dimensional deconstruction by utilizing the knowledge of graph theory. In the dimensional deconstruction, one uses the moose diagram to exhibit the structure of the theory space'. We generalize the moose diagram to a general graph with oriented edges. In the present paper, we consider only the U1 gauge symmetry. We also introduce supersymmetry into our model by use of superfields. We suppose that vector superfields reside at the vertices and chiral superfields at the edges of a given graph. Then we can consider multivector, multiHiggs models. In our model, U1p where p is the number of vertices is broken to a single U1. Therefore for specific graphs, we get vortexlike classical solutions in our model. We show some examples of the graphs admitting the vortex solutions of simple structure as the Bogomolnyi solution.

Dipolar Dark Matter and Dark Energy ; In previous work L. Blanchet and A. Le Tiec, Phys. Rev. D 78, 024031 2008, a model of dark matter and dark energy based on the concept of gravitational polarization was investigated. This model was shown to recover the concordance cosmological scenario LambdaCDM at cosmological scales, and the phenomenology of the modified Newtonian dynamics MOND at galactic scales. In this article we prove that the model can be formulated with a simple and physically meaningful matter action in general relativity. We also provide alternative derivations of the main results of the model, and some details on the variation of the action.

Bianchi II with time varying constants. Selfsimilar approach ; We study a perfect fluid Bianchi II models with time varying constants under the selfsimilarity approach. In the first of the studied model, we consider that only vary G and Lambda. The obtained solution is more general that the obtained one for the classical solution since it is valid for an equation of state omegain1,infty while in the classical solution omegain13,1 . Taking into account the current observations, we conclude that G must be a growing time function while Lambda is a positive decreasing function. In the second of the studied models we consider a variable speed of light VSL. We obtain a similar solution as in the first model arriving to the conclusions that c must be a growing time function if Lambda is a positive decreasing function.

Evidence of gravitons as fused photons in four dimensions ; A model of graviton momentum transfer was constructed to investigate a conjecture that gravitons are fused photons propagating in four dimensions. The model describes gravitational attraction between two bodies, each of simplified geometric shape and comprised of a calculable number of massive particles quarks and leptons, as a probabilistic quantized mechanism of graviton scattering that gives rise to gravitational momentum flux. EarthHuman, MoonHuman, and EarthMoon gravitational systems were investigated to solve for the wavelength of photons that comprise the graviton. The calculated wavelength for each system was approximately equal to the predicted value of the Planck length, which is interpreted as evidence that gravitons may be formed as fused four dimensional photons. The results corroborate current thinking about the temperature at which gravity separated from a unified force during the Big Bang, while explaining the weakness of the gravitational force from the atomic to the subplanetary scale. Extension of the model produces unique, testable predictions arising from the averaged quantum properties of the graviton as fused photons, and the general model approach may be compatible with other efforts to describe the inner structure of the graviton.

A multimode model for projective photoncounting measurements ; We present a general model to account for the multimode nature of the quantum electromagnetic field in projective photoncounting measurements. We focus on photonsubtraction experiments, where nongaussian states are produced conditionally. These are useful states for continuousvariable quantum information processing. We present a general method called mode reduction that reduces the multimode model to an effective twomode problem. We apply this method to a multimode model describing broadband parametric downconversion, thereby improving the analysis of existing experimental results. The main improvement is that spatial and frequency filters before the photon detector are taken into account explicitly. We find excellent agreement with previously published experimental results, using fewer free parameters than before, and discuss the implications of our analysis for the optimized production of states with negative Wigner functions.

Prediction of spatiotemporal patterns of neural activity from pairwise correlations ; We designed a modelbased analysis to predict the occurrence of population patterns in distributed spiking activity. Using a maximum entropy principle with a Markovian assumption, we obtain a model that accounts for both spatial and temporal pairwise correlations among neurons. This model is tested on data generated with a Glauber spinglass system and is shown to correctly predict the occurrence probabilities of spatiotemporal patterns significantly better than Ising models taking into account only pairwise correlations. This increase of predictability was also observed on experimental data recorded in parietal cortex during slowwave sleep. This approach can also be used to generate surrogates that reproduce the spatial and temporal correlations of a given data set.

A dynamic nonlinear model for saturation in industrial growth ; A general nonlinear logistic equation has been proposed to model longtime saturation in industrial growth. An integral solution of this equation has been derived for any arbitrary degree of nonlinearity. A time scale for the onset of nonlinear saturation in industrial growth can be estimated from an equipartition condition between nonlinearity and purely exponential growth. Precise predictions can be made about the limiting values of the annual revenue and the human resource content that an industrial organisation may attain. These variables have also been modelled to set up an autonomous firstorder dynamical system, whose equilibrium condition forms a stable node an attractor state in a related phase portrait. The theoretical model has received close support from all relevant data pertaining to the wellknown global company, IBM.

A penalized exponential risk bound in parametric estimation ; The paper offers a novel unified approach to studying the accuracy of parameter estimation by the quasi likelihood method. Important features of the approach are 1 The underlying model is not assumed to be parametric. 2 No conditions on parameter identifiability are required. The parameter set can be unbounded. 3 The model assumptions are quite general and there is no specific structural assumptions like independence or weak dependence of observations. The imposed conditions on the model are very mild and can be easily checked in specific applications. 4 The established risk bounds are nonasymptotic and valid for large, moderate and small samples. 5 The main result is the concentration property of the quasi MLE giving an nonasymptotic exponential bound for the probability that the considered estimate deviates out of a small neighborhood of the true point. In standard situations under mild regularity conditions, the usual consistency and rate results can be easily obtained as corollaries from the established risk bounds. The approach and the results are illustrated on the example of generalized linear and singleindex models.

Geometric model of the structure of the neutron ; The paper examines the geometrical properties of a sixdimensional KaluzaKlein type model. They may have an impact on the model of the structure of a neutron and its excited states in the realm of one particle physics. The statistical reason for the sixdimensionality and the stability of the solution is given. The derivation of the weak limit approximation of the general wave mechanical quantum mechanical approach, defined in the context of losing its selfconsistency here gravitational, is presented. The non selfconsistent case for the KleinGordon equation is defined. The derivation of the energy of states and the analysis of the spin origin of the analyzed fields configuration is presented as the manifestation of both the geometry of the internal twodimensional space and kinematics of fields inside it. The problem of the departure from the gravitational selfconsistent calculations of the metric tensor and of other fields of the configuration is discussed. The implementation of the model for the description of a neutron and its excited states, including their spins and energies, is given. The informational reason for the existence of the internal extra space dimensions is proposed.

Dark energy from a quintessence phantom field rolling near potential minimum maximum ; We examine dark energy models in which a quintessence or a phantom field, phi, rolls near the vicinity of a local minimum or maximum, respectively, of its potential Vphi. Under the approximation that 1VdVdphi ll 1, although 1Vd2 Vdphi2 can be large, we derive a general expression for the equation of state parameter w as a function of the scale factor for these models. The dynamics of the field depends on the value of 1Vd2 Vdphi2 near the extremum, which describes the potential curvature. For quintessence models, when 1Vd2 Vdphi234 at the potential minimum, the equation of state parameter wa evolves monotonically, while for 1Vd2 Vdphi234, wa has oscillatory behavior. For phantom fields, the dividing line between these two types of behavior is at 1Vd2 Vdphi2 34. Our analytical expressions agree within 1 with the exact numericallyderived behavior, for all of the particular cases examined, for both quintessence and phantom fields. We present observational constraints on these models.

Adaptive pointwise estimation in timeinhomogeneous conditional heteroscedasticity models ; This paper offers a new method for estimation and forecasting of the volatility of financial time series when the stationarity assumption is violated. Our general local parametric approach particularly applies to general varyingcoefficient parametric models, such as GARCH, whose coefficients may arbitrarily vary with time. Global parametric, smooth transition, and changepoint models are special cases. The method is based on an adaptive pointwise selection of the largest interval of homogeneity with a given rightend point by a local changepoint analysis. We construct locally adaptive estimates that can perform this task and investigate them both from the theoretical point of view and by Monte Carlo simulations. In the particular case of GARCH estimation, the proposed method is applied to stockindex series and is shown to outperform the standard parametric GARCH model.

Gravity from Breaking of Local Lorentz Symmetry ; We present a model of gravity based on spontaneous Lorentz symmetry breaking. We start from a model with spontaneously broken symmetries for a massless 2tensor with a linear kinetic term and a nonderivative potential, which is shown to be equivalent to linearized general relativity, with the NambuGoldstone NG bosons playing the role of the gravitons. We apply a bootstrap procedure to the model based on the principle of consistent coupling to the total energy energymomentum tensor. Demanding consistent application of the bootstrap to the potential term severely restricts the form of the latter. Nevertheless, suitable potentials exists that permit stable vacua. It is shown that the resulting model is equivalent, at low energy, to General Relativity in a fixed gauge.

Coupling dark energy with Standard Model states ; In this contribution one examines the coupling of dark energy to the gauge fields, to neutrinos, and to the Higgs field. In the first case, one shows how a putative evolution of the fundamental couplings of strong and weak interactions via coupling to dark energy through a generalized Bekensteintype model may cause deviations on the statistical nuclear decay RutherfordSoddy law. Existing bounds for the weak interaction exclude any significant deviation. For neutrinos, a perturbative approach is developed which allows for considering viable varying mass neutrino models coupled to any quintessencetype field. The generalized Chaplygin model is considered as an example. For the coupling with the Higgs field one obtains an interesting cosmological solution which includes the unification of dark energy and dark matter.

Ricci Dark Energy in braneworld models with a GaussBonnet term in the bulk ; We investigate the Ricci Dark Energy RDE in the braneworld models with a GaussBonnet term in the Bulk. We solve the generalized Friedmann equation on the brane analytically and find that the universe will finally enter into a pure de Sitter spacetime in stead of the big rip that appears in the usual 4D Ricci dark energy model with parameter alpha12. We also consider the Hubble horizon as the IR cutoff in holographic dark energy model and find it can not accelerate the universe as in the usual case without interacting.

From chiral quark models to highenergy processes ; We show the results of lowenergy chiral quark models for soft matrix elements involving pions and photons. Such soft elements, upon convolution with the hard matrix elements, are relevant in various highenergy processes. We focus on quantities related to the generalized parton distributions of the pion the parton distribution functions, the parton distribution amplitudes, and the generalized form factors. Wherever possible, the model predictions are confronted with the data or lattice simulations, where surprisingly good agreement is achieved. The QCD evolution from the low quark model scale up to the scale of the data is crucial for this agreement.

Influence on observation from IR divergence during inflation Multi field inflation ; We propose one way to regularize the fluctuations generated during inflation, whose infrared IR corrections diverge logarithmically. In the case of a single field inflation model, recently, we proposed one solution to the IR divergence problem. There, we introduced new perturbative variables which better mimic actual observable fluctuations, and proved the regularity of correlation functions with respect to these variables. In this paper, we extend our previous discussions to a multi field inflation model. We show that, as long as we consider the case that the nonlinear interaction acts for a finite duration, observable fluctuations are free from IR divergences in the multi field model, too. In contrast to the single field model, to discuss observables, we need to take into account the effects of quantum decoherence which pick up a unique history of the universe from various possibilities contained in initial quantum state set naturally in the early stage of the universe.

CPN1 Models at a Lifshitz Point ; We consider CPN1 models in d1 dimensions around Lifshitz fixed points with dynamical critical exponent z, in the largeN expansion. It is shown that these models are asymptotically free and dynamically generate a mass for the CPN1 fields for all dz. We demonstrate that, for zd2, the initially nondynamical gauge field acquires kinetic terms in a way similar to usual CPN1 models in 11 dimensions. Lorentz invariance emerges generically in the lowenergy electrodynamics, with a nontrivial dielectric constant given by the inverse mass gap and a magnetic permeability which has a logarithmic dependence on scale. At a special multicritical point, the lowenergy electrodynamics also has z2, and an essentially singular dependence of the effective action on BepsilonijpartialiAj.

b to s Transitions in Familydependent U1prime Models ; We analyze flavorchangingneutralcurrent FCNC effects in the bto s transitions that are induced by family nonuniversal U1' gauge symmetries. After systematically developing the necessary formalism, we present a correlated analysis for the Delta B 1, 2 processes. We adopt a modelindependent approach in which we only require familyuniversal charges for the first and second generations and small fermion mixing angles. We analyze the constraints on the resulting parameter space from Bs bar Bs mixing and the timedependent CP asymmetries of the penguindominated Bd to pi, phi, eta', rho, omega, f0KS decays. Our results indicate that the currently observed discrepancies in some of these modes with respect to the Standard Model predictions can be consistently accommodated within this general class of models.

Testing an exact fRgravity model at Galactic and local scales ; The weak field limit for a pointlike source of a fR propto R32gravity model is studied. We aim to show the viability of such a model as a valid alternative to GR dark matter at Galactic and local scales. Without considering dark matter, within the weak field approximation, we find general exact solutions for gravity with standard matter, and apply them to some astrophysical scales, recovering the consistency of the same fRgravity model with cosmological results.In particular, we show that it is possible to obtain flat rotation curves for galaxies, and consistency with Solar System tests, as in the socalled Chameleon Approach. In fact, the peripheral velocity vinfty is shown to be expressed as vinfty lambda sqrtM, so that the TullyFisher relation is recovered. The results point out the possibility of achieving alternative theories of gravity in which exotic ingredients like dark matter and dark energy are not necessary, while their coarsegrained astrophysical and cosmological effects can be related to a geometric origin.

Scaling behaviour of threedimensional group field theory ; Group field theory is a generalization of matrix models, with triangulated pseudomanifolds as Feynman diagrams and state sum invariants as Feynman amplitudes. In this paper, we consider Boulatov's threedimensional model and its FreidelLouapre positive regularization hereafter the BFL model with a ultraviolet' cutoff, and study rigorously their scaling behavior in the large cutoff limit. We prove an optimal bound on large order Feynman amplitudes, which shows that the BFL model is perturbatively more divergent than the former. We then upgrade this result to the constructive level, using, in a selfcontained way, the modern tools of constructive field theory we construct the Borel sum of the BFL perturbative series via a convergent cactus' expansion, and establish the ultraviolet' scaling of its Borel radius. Our method shows how the sum over trian gulations' in quantum gravity can be tamed rigorously, and paves the way for the renormalization program in group field theory.

The nonunique Universe ; The purpose of this paper is to elucidate, by means of concepts and theorems drawn from mathematical logic, the conditions under which the existence of a multiverse is a logical necessity in mathematical physics, and the implications of Godel's incompleteness theorem for theories of everything. Three conclusions are obtained in the final section i the theory of the structure of our universe might be an undecidable theory, and this constitutes a potential epistemological limit for mathematical physics, but because such a theory must be complete, there is no ontological barrier to the existence of a final theory of everything; ii in terms of mathematical logic, there are two different types of multiverse classes of nonisomorphic but elementarily equivalent models, and classes of model which are both nonisomorphic and elementarily inequivalent; iii for a hypothetical theory of everything to have only one possible model, and to thereby negate the possible existence of a multiverse, that theory must be such that it admits only a finite model.

Supersymmetric N2 gauge theory with arbitrary gauge group ; A new universal model to implement the SeibergWitten approach to lowenergy properties of the supersymmetric N2 gauge theory with an arbitrary compact simple gauge group, classical or exceptional, is suggested. It is based on the hyperelliptic curve, whose genus equals the rank of the gauge group. The weak and strong coupling limits are reproduced. The magnetic and electric charges of light dyons, which are present in the proposed model comply with recent predictions derived from the general properties of the theory. The discrete chiral symmetry is implemented, the duality condition is reproduced, and connections between monodromies at weak and strong coupling are established. It is found that the spectra of monopoles and dyons are greatly simplified when vectors representing the scalar and dual fields in the Cartan algebra are aligned along the Weyl vector. This general feature of the theory is used for an additional verification of the model. The model predicts the identical analytic structures of the coupling constants for the theories based on the SUr1 and Sp2r gauge groups.

Hidden variable models for quantum mechanics can have local parts ; We criticize Colbeck and Renner's CR's statement that any hidden variable model can only be compatible with quantum mechanics if its local part is trivial Phys. Rev. Lett. 101, 050403 2008. We note that CR's attempt to divide a nonlocal hidden variable model into a local part and a nonlocal part contains a restriction on the latter. This restriction implies that the division is really into a local part and a nonsignaling nonlocal part. CR's nonsignaling requirement on the nonlocal part cannot be physically motivated, since the hidden variables cannot be accessed by experimenters. Nor is it a natural mathematical generalization from the local hidden variable case, since it is simple to make a generalization without CR's requirement. We give an explicit nonlocal hidden variable model that, in the case the restriction is not enforced, contains nontrivial local hidden variables.

Implications of SpaceTime foam for Entanglement Correlations of Neutral Kaons ; The role of CPT invariance and consequences for bipartite entanglement of neutral K mesons are discussed. A relaxation of CPT leads to a modification of the entanglement which is known as the omega effect. The relaxation of assumptions required to prove the CPT theorem are examined within the context of models of spacetime foam. It is shown that the evasion of the EPR type entanglement implied by CPT which is connected with spin statistics is rather elusive. Relaxation of locality through noncommutative geometry or the introduction of decoherence by themselves do not lead to a destruction of the entanglement. So far we find only one model which is based on noncritical strings and Dparticle capture and recoil that leads to a stochastic contribution to the spacetime metric and consequent change in the neutral meson bipartite entanglement. The lack of an omega effect is demonstrated for a class of models based on thermal like baths which are generally considered as generic models of decoherence.

Twodimensional perturbations in a scalar model for shear banding ; We present an analytical study of a toy model for shear banding, without normal stresses, which uses a piecewise linear approximation to the flow curve shear stress as a function of shear rate. This model exhibits multiple stationary states, one of which is linearly stable against general twodimensional perturbations. This is in contrast to analogous results for the JohnsonSegalman model, which includes normal stresses, and which has been reported to be linearly unstable for general twodimensional perturbations. This strongly suggests that the linear instabilities found in the JohnsonSegalman can be attributed to normal stress effects.

Thermal inflation and baryogenesis in heavy gravitino scenario ; We present a thermal inflation model that incorporates the AffleckDine leptogenesis in heavy gravitinomoduli scenario, which solves the moduliinduced gravitino problem while producing a correct amount of baryon asymmetry and relic dark matter density. The model involves two singlet flat directions stabilized by radiative corrections associated with supersymmetry breaking, one direction that generates the Higgs mu and B parameters, and the other direction that generates the scale of spontaneous lepton number violation. The dark matter is provided by the lightest flatino which might be identified as the axino if the model is assumed to have a U1PQ symmetry to solve the strong CP problem. We derive the conditions for the model to satisfy various cosmological constraints coming from the BigBang nucleosynthesis and the dark matter abundance.

Optical models of the big bang and nontrivial spacetime metrics based on metamaterials ; Optics of metamaterials is shown to provide interesting table top models of many nontrivial spacetime metrics. The range of possibilities is broader than the one allowed in classical general relativity. For example, extraordinary waves in indefinite metamaterials experience an effective metric, which is formally equivalent to the two times physics model in 22 dimensions. An optical analogue of a big bang event is presented during which a 21 Minkowski spacetime is created together with large number of particles populating this spacetime. Such metamaterial models enable experimental exploration of the metric phase transitions to and from the Minkowski spacetime as a function of temperature andor light frequency.

Weakuniversal critical behavior and quantum critical point of the exactly soluble spin12 IsingHeisenberg model with the pair XYZ Heisenberg and quartic Ising interactions ; Spin12 IsingHeisenberg model with XYZ Heisenberg pair interaction and two different Ising quartic interactions is exactly solved with the help of the generalized starsquare transformation, which establishes a precise mapping equivalence with the corresponding eightvertex model on a square lattice generally satisfying Baxter's zerofield symmetric condition. The investigated model exhibits a remarkable weakuniversal critical behavior with two marked wings of critical lines along which critical exponents vary continuously with the interaction parameters. Both wings of critical lines merge together at a very special quantum critical point of the infinite order, which can be characterized through diverging critical exponents. The possibility of observing reentrant phase transitions in a close vicinity of the quantum critical point is related to a relative strength of the exchange anisotropy in the XYZ Heisenberg pair interaction.

Z2BiGradings, Majorana Modules and the Standard Model Action ; The action functional of the Standard Model of particle physics is intimately related to a specific class of first order differential operators called Dirac operators of Pauli type PauliDirac operators. The aim of this article is to carefully analyze the geometrical structure of this class of Dirac operators on the basis of real Dirac operators of simple type. On the basis of simple type Dirac operators, it is shown how the Standard Model action STM action may be viewed as generalizing the EinsteinHilbert action in a similar way the EinsteinHilbert action is generalized by a cosmological constant. Furthermore, we demonstrate how the geometrical scheme presented allows to naturally incorporate also Majorana mass terms within the Standard Model. For reasons of consistency these Majorana mass terms are shown to dynamically contribute to the EinsteinHilbert action by a true cosmological constant. Due to its specific form, this cosmological constant can be very small. Nonetheless, this cosmological constant may provide a significant contribution to dark matterenergy. In the geometrical description presented this possibility arises from a subtle interplay between Dirac and Majorana masses.

Color Octet Leptogenesis ; We study the implications for generating the cosmological baryon asymmetry through leptogenesis in the recent model of Fileviez Perez and Wise, which provides a new mechanism for generating neutrino masses at oneloop by introducing new color octet fermion and scalar fields. We find that there are significant differences with respect to other models for leptogenesis low scale leptogenesis can occur naturally and the CP asymmetry can be large as there is no upper bound arising from neutrino masses. The CP asymmetry is insensitive to the phases in the neutrino mixing matrix. We investigate in detail the minimal model that can simultaneously fit low scale neutrino physics, the mu to e gamma bound and leptogenesis. The model can provide outstanding collider signatures and the value of the CPasymmetry can be more constrained from lepton flavour violating processes than from neutrino physics.

Shrinkage Tuning Parameter Selection in Precision Matrices Estimation ; Recent literature provides many computational and modeling approaches for covariance matrices estimation in a penalized Gaussian graphical models but relatively little study has been carried out on the choice of the tuning parameter. This paper tries to fill this gap by focusing on the problem of shrinkage parameter selection when estimating sparse precision matrices using the penalized likelihood approach. Previous approaches typically used Kfold crossvalidation in this regard. In this paper, we first derived the generalized approximate crossvalidation for tuning parameter selection which is not only a more computationally efficient alternative, but also achieves smaller error rate for model fitting compared to leaveoneout crossvalidation. For consistency in the selection of nonzero entries in the precision matrix, we employ a Bayesian information criterion which provably can identify the nonzero conditional correlations in the Gaussian model. Our simulations demonstrate the general superiority of the two proposed selectors in comparison with leaveoneout crossvalidation, tenfold crossvalidation and Akaike information criterion.

Fermion Masses and Flavor Mixings in a Model with S4 Flavor Symmetry ; We present a supersymmetric model of quark and lepton based on S4times Z3times Z4 flavor symmetry. The S4 symmetry is broken down to Klein four and Z3 subgroups in the neutrino and the charged lepton sectors respectively. TriBimaximal mixing and the charged lepton mass hierarchies are reproduced simultaneously at leading order. Moreover, a realistic pattern of quark masses and mixing angles is generated with the exception of the mixing angle between the first two generations, which requires a small accidental enhancement. It is remarkable that the mass hierarchies are controlled by the spontaneous breaking of flavor symmetry in our model. The next to leading order contributions are studied, all the fermion masses and mixing angles receive corrections of relative order lambda2c with respect to the leading order results. The phenomenological consequences of the model are analyzed, the neutrino mass spectrum can be normal hierarchy or inverted hierarchy, and the combined measurement of the 0nu2beta decay effective mass mbetabeta and the lightest neutrino mass can distinguish the normal hierarchy from the inverted hierarchy.

Generalized bumblebee models and Lorentzviolating electrodynamics ; The breaking of Lorentz symmetry via a dynamical mechanism, with a tensor field which takes on a nonzero expectation value in vacuum, has been a subject of significant research activity in recent years. In certain models of this type, the perturbations of the Lorentzviolating field about this background may be identified with known forces. I present the results of applying this interpretation to the generalized bumblebee models found in a prior work. In this model, the perturbations of a Lorentzviolating vector field can be interpreted as a photon field. However, the speed of propagation of this bumblebee photon is directiondependent and differs from the limiting speed of conventional matter, leading to measurable physical effects. Bounds on the parameters of this theory can then be derived from resonator experiments, accelerator physics, and cosmic ray observations.

A general study on the volume dependence of spectral weights in lattice field theory ; It has been suggested that the volume dependence of the spectral weight could be utilized to distinguish single and multiparticle states in Monte Carlo simulations. In a recent study using a solvable model, the Lee model, we found that this criteria is applicable only for stable particles and narrow resonances, not for the broad resonances. In this paper, the same question is addressed within the finite size formalism outlined by Luscher. Using a quantum mechanical scattering model, the conclusion that was found in previous Lee model study is recovered. Then, following similar arguments as in Luscher's, it is argued that the result is valid for a general massive quantum field theory under the same conditions as the Luscher's formulae. Using the spectral weight function, a possibility of extracting resonance parameters is also pointed out.

Observation of Lightning Ball Ball Lightning A new phenomenological description of the phenomenon ; The author physicisthas observed the very strange,beautiful and frightening Lightning Ball LB. He has never forgotten this phenomenon. During his working life he could not devote himself to the problem of LBformation.Only two years ago as he has been reading different unbelievable models of LBformation, he decided to work on this problem. By studying the literature and the crucial points of his observation the author succeeded in creating a completely new model of Lightning BallLB and Ball LightningBLformation based on the symmetry breaking of the hydrodynamic vortex ring.This agrees fully with the observation and overcomes the shortcomings of current models of LB formation. This model provides answers to the questions Why are LBs so rarely observed,why do BLs in rare cases have such a high energy and how can we generate LB in the laboratory Moreover the author differentiates between LB and BL, the latter having a high energy and occuring in 5 of the observations. Keywords ball lightning, hydrodynamic vortex ring, symmetry breaking, electroluminescence, triboelectrification.

Reconstructing quintom from WMAP 5year observations Generalized ghost condensate ; In the 5year WMAP data analysis, a new parametrization form for dark energy equationofstate was used, and it has been shown that the equationofstate, wz, crosses the cosmologicalconstant boundary w1. Based on this observation, in this paper, we investigate the reconstruction of quintom dark energy model. As a singlerealscalarfield model of dark energy, the generalized ghost condensate model provides us with a successful mechanism for realizing the quintomlike behavior. Therefore, we reconstruct this scalarfield quintom dark energy model from the WMAP 5year observational results. As a comparison, we also discuss the quintom reconstruction based on other specific dark energy ansatzs, such as the CPL parametrization and the holographic dark energy scenarios.

Renormalization of Lorentz noninvariant actions and manifest Tduality ; We study general twodimensional sigmamodels which do not possess manifest Lorentz invariance. We show how demanding that Lorentz invariance is recovered as an emergent onshell symmetry constrains these sigmamodels. The resulting actions have an underlying grouptheoretic structure and resemble PoissonLie Tduality invariant actions. We consider the oneloop renormalization of these models and show that the quantum Lorentz anomaly is absent. We calculate the running of the couplings in general and show, with certain nontrivial examples, that this agrees with that of the Tdual models obtained classically from the duality invariant action. Hence, in these cases solving constraints before and after quantization are commuting operations.

Iterative Methods for the Forcebased Quasicontinuum Approximation ; Forcebased atomisticcontinuum hybrid methods are the only known pointwise consistent methods for coupling a general atomistic model to a finite element continuum model. For this reason, and due to their algorithmic simplicity, forcebased coupling methods have become a popular class of atomisticcontinuum hybrid models as well as other types of multiphysics models. However, the recently discovered unusual stability properties of the linearized forcebased quasicontinuum QCF approximation, especially its indefiniteness, present a challenge to the development of efficient and reliable iterative methods. We present analytic and computational results for the generalized minimal residual GMRES solution of the linearized QCF equilibrium equations. We show that the GMRES method accurately reproduces the stability of the forcebased approximation and conclude that an appropriately preconditioned GMRES method results in a reliable and efficient solution method.

Non singular bounce in modified gravity ; We investigate bouncing solutions in the framework of the nonsingular gravity model of Brandenberger, Mukhanov and Sornborger. We show that a spatially flat universe filled with ordinary matter undergoing a phase of contraction reaches a stage of minimal expansion factor before bouncing in a regular way to reach the expanding phase. The expansion can be connected to the usual radiation and matterdominated epochs before reaching a final expanding de Sitter phase. In general relativity GR, a bounce can only take place provided that the spatial sections are positively curved, a fact that has been shown to translate into a constraint on the characteristic duration of the bounce. In our model, on the other hand, a bounce can occur also in the absence of spatial curvature, which means that the timescale for the bounce can be made arbitrarily short or long. The implication is that constraints on the bounce characteristic time obtained in GR rely heavily on the assumed theory of gravity. Although the model we investigate is fourth order in the derivatives of the metric and therefore unstable visavis the perturbations, this generic bounce dynamics should extend to stringmotivated non singular models which can accommodate a spatially flat bounce.

Constraints on Dark Energy and Modified Gravity models by the Cosmological Redshift Drift test ; We study cosmological constraints on the various accelerating models of the universe using the time evolution of the cosmological redshift of distant sources. The important characteristic of this test is that it directly probes the expansion history of the universe. In this work we analyze the various models of the universe which can explain the late time acceleration, within the framework of General Theory of Relativity GR XCDM, scalar field potentials and beyond GR fR gravity model.

Multifractality of the multiplicative autoregressive point processes ; Multiplicative processes and multifractals have earned increased popularity in applications ranging from hydrodynamic turbulence to computer network traffic, from image processing to economics. We analyse the multifractality of the recently proposed point process models generating the signals exhibiting 1fb noise. The models may be used for modeling and analysis of stochastic processes in different systems. We show that the multiplicative point process models generate multifractal signals, in contrast to the formally constructed signals with 1fb noise and signals consisting of sum of the uncorrelated components with a widerange distribution of the relaxation times.

An Iterative Algorithm for Fitting Nonconvex Penalized Generalized Linear Models with Grouped Predictors ; Highdimensional data pose challenges in statistical learning and modeling. Sometimes the predictors can be naturally grouped where pursuing the betweengroup sparsity is desired. Collinearity may occur in realworld highdimensional applications where the popular l1 technique suffers from both selection inconsistency and prediction inaccuracy. Moreover, the problems of interest often go beyond Gaussian models. To meet these challenges, nonconvex penalized generalized linear models with grouped predictors are investigated and a simpletoimplement algorithm is proposed for computation. A rigorous theoretical result guarantees its convergence and provides tight preliminary scaling. This framework allows for grouped predictors and nonconvex penalties, including the discrete l0 and the l0l2' type penalties. Penalty design and parameter tuning for nonconvex penalties are examined. Applications of superresolution spectrum estimation in signal processing and cancer classification with joint gene selection in bioinformatics show the performance improvement by nonconvex penalized estimation.

Nested algebraic Bethe ansatz for open GLN spin chains with projected Kmatrices ; We consider an open spin chain model with GLN bulk symmetry that is broken to GLM x GLNM by the boundary, which is a generalization of a model arising in stringgauge theory. We prove the integrability of this model by constructing the corresponding commuting transfer matrix. This construction uses operatorvalued projected Kmatrices. We solve this model for general values of N and M using the nested algebraic Bethe ansatz approach, despite the fact that the Kmatrices are not diagonal. The key to obtaining this solution is an identity based on a certain factorization property of the reduced Kmatrices into products of Rmatrices. Numerical evidence suggests that the solution is complete.

Reevaluating the Cosmological Origin of Dark Matter ; The origin of dark matter as a thermal relic offers a compelling way in which the early universe was initially populated by dark matter. Alternative explanations typically appear exotic compared to the simplicity of thermal production. However, recent observations and progress from theory suggest that it may be necessary to be more critical. This is important because ongoing searches probing the microscopic properties of dark matter typically rely on the assumption of dark matter as a single, unique, thermal relic. On general grounds I will argue that nonthermal production of dark matter seems to be a robust prediction of physics beyond the standard model. However, if such models are to lead to realistic phenomenology, they must sit in a restrictive theoretical framework. As we will show, as a consequence of such restrictions, viable models will result in concrete and testable predictions. Although many challenges remain, the nonthermal component of such models may offer a new way to test string theories that are formulated to provide realistic particle physics near the electroweak scale.

Discovering the Higgs Boson in New Physics Events using Jet Substructure ; We present a novel method to discover the Higgs boson in new physics event samples at the LHC. Our technique applies to broad classes of models where the Higgs has a significant branching fraction to bbbar. We exploit the recently developed techniques for discovering a boosted Higgs using jet substructure. Our requirements of new physics are quite general there must be features in the new physics event sample that allow a clean separation from standard model background, and there should be Higgs bosons produced in association with the new physics. We demonstrate that this method superbly finds and identifies the lightest Higgs boson in the minimal supersymmetric standard model. We focus on two case studies with a gravitino LSP, however, generalizations to other LSPs and to other models of new physics are also briefly discussed. In some circumstances, discovery of the lightest Higgs is possible well before conventional search strategies uncover convincing evidence.

Inverse problem reconstruction of dark energy models ; We review how we can construct the gravity models which reproduces the arbitrary development of the universe. We consider the reconstruction in the Einstein gravity coupled with generalized perfect fluid, scalarEinstein gravity, scalarEinsteinGaussBonnet gravity, EinsteinFGgravity, and FRgravity. Very explicit formulas are given to reconstruct the models, which could be used when we find the detailed data of the development of the universe by future observations. Especially we find the formulas using efoldings, which has a direct relation with observed redshift. As long as we observe the time development of the Hubble rate H, there exists a variety of models describing the arbitrary development of universe.

Threeband superconductivity and the order parameter that breaks timereversal symmetry ; We consider a model of multiband superconductivity, inspired by iron pnictides, in which three bands are connected via repulsive pairscattering terms. Generically, three distinct superconducting states arise within such a model. Two of them are straightforward generalizations of the twogap order parameter while the third one corresponds to a timereversal symmetry breaking order parameter, altogether absent within the twoband model. Potential observation of such a genuinely frustrated state would be a particularly vivid manifestation of the repulsive interactions being at the root of ironbased high temperature superconductivity. We construct the phase diagram of this model and discuss its relevance to the iron pnictides family of high temperature superconductors. We also study the case of the Josephson coupling between a twoband s' or extended swave superconductor and a singlegap swave superconductor, and the associated phase diagram.

de Sitter expansion with anisotropic fluid in Bianchi typeI spacetime ; Some features of the Bianchi typeI universes in the presence of a fluid that wields an anisotropic equation of state EoS parameter are discussed in the context of general relativity. The models that exhibit de Sitter volumetric expansion due to the constant effective energy density the sum of the energy density of the fluid and the anisotropy energy density are of particular interest. We also introduce two locally rotationally symmetric models, which exhibit de Sitter volumetric expansion in the presence of a hypothetical fluid that has been obtained by minimally altering the conventional vacuum energy. In the first model, the directional EoS parameter on the x axis is assumed to be 1, while the ones on the other axes and the energy density of the fluid are allowed to be functions of time. In the second model, the energy density of the fluid is assumed to be constant, while the directional EoS parameters are allowed to be functions of time.

The Underlying Dynamics of Credit Correlations ; We propose a hybrid model of portfolio credit risk where the dynamics of the underlying latent variables is governed by a one factor GARCH process. The distinctive feature of such processes is that the longterm aggregate return distributions can substantially deviate from the asymptotic Gaussian limit for very long horizons. We introduce the notion of correlation surface as a convenient tool for comparing portfolio credit loss generating models and pricing synthetic CDO tranches. Analyzing alternative specifications of the underlying dynamics, we conclude that the asymmetric models with TARCH volatility specification are the preferred choice for generating significant and persistent credit correlation skews. The characteristic dependence of the correlation skew on term to maturity and portfolio hazard rate in these models has a significant impact on both relative value analysis and risk management of CDO tranches.

Renormalization in General Gauge Mediation ; We revisit General Gauge Mediation GGM in light of the supersymmetric linear sigma model by utilizing the current superfield. The current superfield in the GGM is identified with supersymmetric extension of the vector symmetry current of the sigma model while spontaneous breakdown of supersymmetry in the GGM corresponds to soft breakdown of the axial vector symmetry of the sigma model. We first derive the current superfield from the supersymmetric linear sigma model and then compute 2point functions of the current superfield using the anticommutation relations of the messenger component fields. After the global symmetry are weakly gauged, the 2point functions of the current superfield are identified with a part of the 2point functions of the associated vector superfield. We renormalize them by dimensional regularization and show that physical gaugino and sfermion masses of the MSSM are expressed in terms of the wavefunction renormalization constants of the component fields of the vector superfield.

Electric charge quantization in SU3c X SU3L X U1X model ; Basing on the general photon eigenstate and anomaly cancellation, it is shown that the electric charge quantization in SU3c X SU3L X U1X model with exotic particles can be obtained independently on parameters alpha and betta. The fixation of hypercharges of fermions fields by the Higgs fields and dependence of the electric charges quantization conditions from the hypercharges of Higgs fields leads to the fact that the electric charge in the considered model can be quantized and fixed only in the presence of Higgs fields. In addition, we have shown that in the considered model the classical constraints following from the Yukawa interactions are equivalent to the conditions following from the parity invariance of electromagnetic interaction. The most general expressions for the gauge bosons masses, eigenstates of neutral fields and the interactions of leptons and quarks with gauge bosons have been derived in the arbitrary case

Switch and template pattern formation in a discrete reaction diffusion system inspired by the Drosophila eye ; We examine a spatially discrete reaction diffusion model based on the interactions that create a periodic pattern in the Drosophila eye imaginal disc. This model is capable of generating a regular hexagonal pattern of gene expression behind a moving front, as observed in the fly system. In order to better understand the novel switch and template mechanism behind this pattern formation, we present here a detailed study of the model's behavior in one dimension, using a combination of analytic methods and numerical searches of parameter space. We find that patterns are created robustly provided that there is an appropriate separation of timescales and that selfactivation is sufficiently strong, and we derive expressions in this limit for the front speed and the pattern wavelength. Moving fronts in patternforming systems near an initial linear instability generically select a unique pattern, but our model operates in a strongly nonlinear regime where the final pattern depends on the initial conditions as well as on parameter values. Our work highlights the important role that cellularization and cellautonomous feedback can play in biological pattern formation.

Percolation on selfdual polygon configurations ; Recently, Scullard and Ziff noticed that a broad class of planar percolation models are selfdual under a simple condition that, in a parametrized version of such a model, reduces to a single equation. They state that the solution of the resulting equation gives the critical point. However, just as in the classical case of bond percolation on the square lattice, selfduality is simply the starting point the mathematical difficulty is precisely showing that selfduality implies criticality. Here we do so for a generalization of the models considered by Scullard and Ziff. In these models, the states of the bonds need not be independent; furthermore, increasing events need not be positively correlated, so new techniques are needed in the analysis. The main new ingredients are a generalization of Harris's Lemma to products of partially ordered sets, and a new proof of a type of RussoSeymourWelsh Lemma with minimal symmetry assumptions.

Extinction in neutrally stable stochastic LotkaVolterra models ; Populations of competing biological species exhibit a fascinating interplay between the nonlinear dynamics of evolutionary selection forces and random fluctuations arising from the stochastic nature of the interactions. The processes leading to extinction of species, whose understanding is a key component in the study of evolution and biodiversity, are influenced by both of these factors. In this paper, we investigate a class of stochastic population dynamics models based on generalized LotkaVolterra systems. In the case of neutral stability of the underlying deterministic model, the impact of intrinsic noise on the survival of species is dramatic it destroys coexistence of interacting species on a time scale proportional to the population size. We introduce a new method based on stochastic averaging which allows one to understand this extinction process quantitatively by reduction to a lowerdimensional effective dynamics. This is performed analytically for two highly symmetrical models and can be generalized numerically to more complex situations. The extinction probability distributions and other quantities of interest we obtain show excellent agreement with simulations.

Superconductivity generated by coupling to a Cooperon in a 2dimensional array of 4leg Hubbard ladders ; Starting from an array of fourleg Hubbard ladders weakly doped away from halffilling and weakly coupled by interladder tunneling, we derive an effective low energy model which contains a partially truncated Fermi surface and a well defined Cooperon excitation formed by a bound pair of holes. An attractive interaction in the Cooper channel is generated on the Fermi surface through virtual scattering into the Cooperon state. Although the model is derived in the weak coupling limit of a fourleg ladder array, an examination of exact results on finite clusters for the strong coupling tJ model suggests the essential features are also present for a strong coupling Hubbard model on a square lattice near halffilling.

Determination of screened Coulomb repulsion energies in organic molecular crystals A real space approach ; We present a general method for determining screened Coulomb parameters in molecular assemblies, in particular organic molecular crystals. This allows us to calculate the interaction parameters used in a generalized Hubbard model description of correlated organic materials. In such a model only the electrons in levels close to the Fermi level are included explicitly, while the effect of all other electrons is included as a renormalization of the model parameters. For the Coulomb integrals this renormalization is mainly due to screening. For molecular materials we can split the screening into intra and intermolecular screening. Here we demonstrate how the intermolecular screening can be calculated by modeling the molecules by distributed pointpolarizabilities and solving the resulting selfconsistent electrostatic screening problem in real space. For the example of the quasi onedimensional molecular metal TTFTCNQ we demonstrate that the method gives remarkably accurate results.

Consistent order estimation and minimal penalties ; Consider an i.i.d. sequence of random variables whose distribution f lies in one of a nested family of models Mq, q1. The smallest index q such that Mq contains f is called the model order. We establish strong consistency of the penalized likelihood order estimator in a general setting with penalties of order etaq log log n, where etaq is a dimensional quantity. Moreover, such penalties are shown to be minimal. In contrast to previous work, an a priori upper bound on the model order is not assumed. The results rely on a sharp characterization of the pathwise fluctuations of the generalized likelihood ratio statistic under entropy assumptions on the model classes. Our results are applied to the geometrically complex problem of location mixture order estimation, which is widely used but poorly understood.