ShantanuT01/DACTYL-Pretraining huggingface dataset:
Umklapp scattering determines the conductivity of clean metals. In typical quasi one-dimensional Fermi liquids with an open Fermi surface, certain pseudo-momenta do not decay by 2-particle collisions even in situations where Umklapp scattering relaxes the momentum of the quasi particles efficiently. Due to this approximate conservation of pseudo-momentum, a certain fraction of the electrical current decays very slowly and a well-pronounced low-frequency peak emerges in the optical conductivity. We develop simple criteria to determine under what conditions approximate pseudo-momentum conservation is relevant and calculate within in Fermi liquid theory the weights of the corresponding low-frequency peaks and the temperature dependence of the various relevant decay rates. Based on these considerations, we obtain a qualitative picture of the frequency and temperature dependence of the optical conductivity of an anisotropic Fermi liquid.
It was shown that a material fatigue fracture diagram can be viewed as a locus of points with $\sigma $ and $\sqrt l$ coordinates' product equal to $K_{1c}/2$, and $\sigma $ and $l$ product -- to $G_{1c}/2$, where $K_{1c}$ and $G_{1c}$ are non-linear fracture mechanics force and energy criteria. It was established that the average number of interatomic bonds destroyed within one alternate stress $\nabla_{1cs}$ cycle is directly proportional to $\sigma $ that is twice as large as a peak value of $\sigma^a$. It was found that low-cycle fatigue is characterized by $\sigma >\sigma_{0.2}$ and $\sigma_{1cs}> 1$, high-cycle fatigue -- by $\sigma = \sigma_{0.2}$ and $\nabla_{1cs} = 1$, and giga-cycle fatigue -- by $\sigma < \sigma_{0.2}$ and $\nabla_{1cs} < 1$. An individual interatomic bond cannot be destroyed part by part but as a single unit. The latter means that in giga-cycle fatigue a single interatomic bond is destroyed within several cycles rather than within a single cycle. The factors $F$ (collapsibility) and $R$ (resistibility) were proposed and mentioned as essential material physical constants. The introduced notion $\nabla_{1cs}$ and the established linear nature of $\nabla_{1cs}$ relationship allow to: a) clarify the fatigue crack growth physical nature in low-, high- and giga-cycle fracture zones; b) determine the nature of a fatigue fracture diagram disruption; c) plot the fatigue fracture diagram using the results obtained in a single specimen cyclic strength test with a selected value of $\sigma \ge \sigma_{0.2}$. For giga-cycle fatigue it is important (with similar purpose in mind) to determine this dependence for $\sigma < \sigma_{0.2}$. It is recommended to use $G_{1c}$ criterion to find the $l_{cr}$ length value which in contrast to $K_{1c}$ has a clear physical nature.
We point out that time-dependent CP asymmetries in B_s to K^{*0} \bar K^{*0} decays probe the presence of new physics in b to s transitions with an unprecedented theoretical accuracy. We show that, contrary to the case of B_d to phi K_S, it is possible to obtain a model-independent prediction for the coefficient S(B_s to K^{*0} \bar K^{*0}) in the Standard Model. We give an estimate of the experimental precision achievable with the next generation of B physics experiments. We also discuss how this approach can be extended to the case of B_s to \bar K^{*0} K^0, B_s to K^{*0} \bar K^0 and B_s to K^0 \bar K^0 decays and the different experimental challenges for these channels.
Charge transport in topological insulators is primarily characterised by so-called topologically projected helical edge states, where charge carriers are correlated in spin and momentum. In principle, dissipation-less current can be carried by these edge states as backscattering from impurities and defects is suppressed as long as time-reversal symmetry is not broken. However, applied magnetic fields or underlying nuclear spin-defects in the substrate can break this time reversal symmetry. In particular, magnetic impurities lead to back-scattering by spin-flip processes. We have investigated the effects of point-wise magnetic impurities on the transport properties of helical edge states in the BHZ model using the Non-Equilibrium Green's Function formalism and compared the results to a semi-analytic approach. Using these techniques we study the influence of impurity strength and spin impurity polarization. We observe a secondary effect of defect-defect interaction that depends on the underlying material parameters which introduces a non-monotonic response of the conductance to defect density. This in turn suggests a qualitative difference in magneto-transport signatures in the dilute and high density spin impurity limits.
We present a framework for training GANs with explicit control over generated images. We are able to control the generated image by settings exact attributes such as age, pose, expression, etc. Most approaches for editing GAN-generated images achieve partial control by leveraging the latent space disentanglement properties, obtained implicitly after standard GAN training. Such methods are able to change the relative intensity of certain attributes, but not explicitly set their values. Recently proposed methods, designed for explicit control over human faces, harness morphable 3D face models to allow fine-grained control capabilities in GANs. Unlike these methods, our control is not constrained to morphable 3D face model parameters and is extendable beyond the domain of human faces. Using contrastive learning, we obtain GANs with an explicitly disentangled latent space. This disentanglement is utilized to train control-encoders mapping human-interpretable inputs to suitable latent vectors, thus allowing explicit control. In the domain of human faces we demonstrate control over identity, age, pose, expression, hair color and illumination. We also demonstrate control capabilities of our framework in the domains of painted portraits and dog image generation. We demonstrate that our approach achieves state-of-the-art performance both qualitatively and quantitatively.
We compute the largest relaxation times for the totally asymmetric exclusion process (TASEP) with open boundary conditions with a DMRG method. This allows us to reach much larger system sizes than in previous numerical studies. We are then able to show that the phenomenological theory of the domain wall indeed predicts correctly the largest relaxation time for large systems. Besides, we can obtain results even when the domain wall approach breaks down, and show that the KPZ dynamical exponent $z=3/2$ is recovered in the whole maximal current phase.
We study the asymptotic behaviour of uniform random maps with a prescribed face-degree sequence, in the bipartite case, as the number of faces tends to infinity. Under mild assumptions, we show that, properly rescaled, such maps converge in distribution towards the Brownian map in the Gromov-Hausdorff sense. This result encompasses a previous one of Le Gall for uniform random $q$-angulations where $q$ is an even integer. It applies also to random maps sampled from a Boltzmann distribution, under a second moment assumption only, conditioned to be large in either of the sense of the number of edges, vertices, or faces. The proof relies on the convergence of so-called "discrete snakes" obtained by adding spatial positions to the nodes of uniform random plane trees with a prescribed child sequence recently studied by Broutin & Marckert. This paper can alternatively be seen as a contribution to the study of the geometry of such trees.
Strong lensing is a powerful tool to address three major astrophysical issues: understanding the spatial distribution of mass at kpc and sub-kpc scale, where baryons and dark matter interact to shape galaxies as we see them; determining the overall geometry, content, and kinematics of the universe; studying distant galaxies, black holes, and active nuclei that are too small or too faint to be resolved or detected with current instrumentation. After summarizing strong gravitational lensing fundamentals, I present a selection of recent important results. I conclude by discussing the exciting prospects of strong gravitational lensing in the next decade.
We generalise a method of Xiao Gang to construct 'prototypes' of fibred surfaces with maximal irregularity without being a product. This enables us, in the case of fibre genus g=3 to describe the possible singular fibres and to calculate the invariants of these surfaces. We also prove structure theorems on the moduli space for fibred surfaces with fibre genus g=2 and g=3.
A semimicroscopical approach is applied to calculate: (i) strength functions for the charge-exchange spin-dipole giant resonances in the 208Pb parent nucleus; (ii) partial and total branching ratios for the direct proton decay of the resonance in 208Bi. The approach is based on continuum-RPA calculations of corresponding reaction-amplitudes and phenomenological description of the doorway-state coupling to many-quasiparticle configurations. The only adjustable parameter needed for the description is found by comparison of the calculated and experimental total widths of the resonance. Other model parameters used in calculations are taken from independent data. The calculated total branching ratio is found to be in reasonable agreement with the experimental value.
The decoupling technique is a fundamental tool in quantum information theory with applications ranging from quantum thermodynamics to quantum many body physics to the study of black hole radiation. In this work we introduce the notion of catalytic decoupling, that is, decoupling in the presence of an uncorrelated ancilla system. This removes a restriction on the standard notion of decoupling, which becomes important for structureless resources, and yields a tight characterization in terms of the max-mutual information. Catalytic decoupling naturally unifies various tasks like the erasure of correlations and quantum state merging, and leads to a resource theory of decoupling.
Multiplicative relations between the roots of a polynomial in $\mathbb{Q}[x]$ have drawn much attention in the field of arithmetic and algebra, while the problem of computing these relations is interesting to researchers in many other fields. In this paper, a sufficient condition is given for a polynomial $f\in\mathbb{Q}[x]$ to have only trivial multiplicative relations between its roots, which is a generalization of those sufficient conditions proposed in [C. J. Smyth, \emph{J. Number Theory}, 23 (1986), pp. 243--254], [G. Baron \emph{et al}., \emph{J. Algebra}, 177 (1995), pp. 827--846] and [J. D. Dixon, \emph{Acta Arith.} 82 (1997), pp. 293--302]. Based on the new condition, a subset $E\subset\mathbb{Q}[x]$ is defined and proved to be genetic (i.e., the set $\mathbb{Q}[x]\backslash E$ is very small). We develop an algorithm deciding whether a given polynomial $f\in\mathbb{Q}[x]$ is in $E$ and returning a basis of the lattice consisting of the multiplicative relations between the roots of $f$ whenever $f\in E$. The numerical experiments show that the new algorithm is very efficient for the polynomials in $E$. A large number of polynomials with much higher degrees, which were intractable before, can be handled successfully with the algorithm.
In this contribution I summarize and discuss the results of the bulk thermodynamic characteristics, meson and nucleon structure in hot matter obtained in the framework of a chiral quark-meson theory. A hybrid NJL model is used in which a Dirac sea of quarks is combined with a Fermi sea of quarks or of nucleons. In the model mesons are described as collective $\bar qq$ excitations and the nucleon appears as a baryon-number-one soliton of $N_c$ valence quarks coupled to both Dirac and Fermi sea. According to the model at some critical density and/or temperature phase transitions from nucleons to quarks as well as from Goldstone to Wigner phase are expected. At finite density the chiral order parameter and the constituent quark mass have a non-monotonic temperature dependence-at temperatures not close to the critical one they are less affected than in cold matter. The quark matter is rather soft against thermal fluctuations and the corresponding chiral phase transition is smooth. The nucleon matter is much stiffer and the phase transition is very sharp. In the case of quark matter a first-order transition is suggested at low temperatures ($T<80$ MeV) which changes to a second-order one at higher temperatures. In contrast to the quark matter in the case of nucleon matter the thermodynamic variables show large discontinuities which is a clear indication for a first-order phase transition. In hot medium at intermediate temperature the nucleon soliton is more bound and less swelled than in the case of cold matter. At some critical temperature, which for nucleon matter coincides with the critical temperature for the phase transition, no more a localized solution is found. According to this model scenario one should expect a first-order phase transition from nucleon to quark matter.
We, based on the photoassociation of fermion atoms into bosonic molecules, propose a scheme to create the steady entanglement between the atom state and the molecule state inside an optical lattice. The stability of entanglement state is guaranteed by sweeping the frequency of Ramman laser beam through resonance according to the second Demkov-Kunike (DK2) nonadiabatic transition model\cite{DK,models}. The probability amplitude of each components can be precisely controlled by adjusting the sweeping parameter.
In this work, we calculated the baryon mass within a non-relativistically quark model using an approach based on the G\"ursey Radicati mass formula (GR). The average energy value of each SU(6) multiplet is described using the SU(6) invariant interaction given by a hypercentral potential. In our series studies we investigate different interactions and situations to gain the best possible model. This goal can be obtained by checking and studying various potentials in different situations. In this paper we present the solution of the Schr\"odinger equation with an hypercentral power low potential. The results of our model (the combination of our proposed hypercentral Potential and generalized GR mass formula to description of the spectrum) show that the strange and non-strange baryons spectra are in general fairly well reproduced. The overall good description of the mass which we obtain shows that our model can also be used to give a fair description of the energies of the excited multiplets up to three GeV and the position of the Roper resonances of the nucleon.
The thermal conductance of straight and corrugated monocrystalline silicon nanowires has been measured between 0.3 K and 5 K. The difference in the thermal transport between corrugated nanowires and straight ones demonstrates a strong reduction in the mean free path of the phonons. This averaged mean free path is remarkably smaller than the smaller diameter of the nanowire, evidencing a phonon thermal transport reduced below the Casimir limit. Monte Carlo simulations highlight that this effect can be attributed to significant multiple scattering of ballistic phonons occuring on the corrugated surfaces. This result suggests an original approach to transforming a monocrystalline material into a phonon glass.
We investigate the non-uniform structures and the equation of state (EOS) of nuclear matter in the context of the first-order phase transitions (FOPT) such as liquid-gas phase transition, kaon condensation, and hadron-quark phase transition. During FOPT the mixed phases appear, where matter exhibits non-uniform structures called ``Pasta'' structures due to the balance of the Coulomb repulsion and the surface tension between two phases. We treat these effects self-consistently, properly taking into account of the Poisson equation and the Gibbs conditions. Consequently, they make the EOS of the mixed phase closer to that of Maxwell construction due to the Debye screening. This is a general feature of the mixed phase consisting of many species of charged particles.
Let $K$ be a fixed number field, assumed to be Galois over $\mathbb Q$. Let $r$ and $f$ be fixed integers with $f$ positive. Given an elliptic curve $E$, defined over $K$, we consider the problem of counting the number of degree $f$ prime ideals of $K$ with trace of Frobenius equal to $r$. Except in the case $f=2$, we show that "on average," the number of such prime ideals with norm less than or equal to $x$ satisfies an asymptotic identity that is in accordance with standard heuristics. This work is related to the classical Lang-Trotter conjecture and extends the work of several authors.
We study sequences of empirical measures of Euler schemes associated to some non-Markovian SDEs: SDEs driven by Gaussian processes with stationary increments. We obtain the functional convergence of this sequence to a stationary solution to the SDE. Then, we end the paper by some specific properties of this stationary solution. We show that, in contrast to Markovian SDEs, its initial random value and the driving Gaussian process are always dependent. However, under an integral representation assumption, we also obtain that the past of the solution is independent to the future of the underlying innovation process of the Gaussian driving process.
We employ the linear sigma model to study the chiral dynamics of two flavors of quarks at finite temperature and density. Our calculations include thermal fluctuations of both the bosonic and fermionic fields. In particular, we determine the phase diagram in the plane of temperature and baryon chemical potential as a function of the pion mass. An interesting phase structure occurs that results in zero, one, or two critical points depending on the value of the vacuum pion mass.
In this paper, we propose a novel video super-resolution method that aims at generating high-fidelity high-resolution (HR) videos from low-resolution (LR) ones. Previous methods predominantly leverage temporal neighbor frames to assist the super-resolution of the current frame. Those methods achieve limited performance as they suffer from the challenge in spatial frame alignment and the lack of useful information from similar LR neighbor frames. In contrast, we devise a cross-frame non-local attention mechanism that allows video super-resolution without frame alignment, leading to be more robust to large motions in the video. In addition, to acquire the information beyond neighbor frames, we design a novel memory-augmented attention module to memorize general video details during the super-resolution training. Experimental results indicate that our method can achieve superior performance on large motion videos comparing to the state-of-the-art methods without aligning frames. Our source code will be released.
We study the effect of the relative velocity of dark matter and baryonic fluids after the epoch of recombination on the evolution of the first bound objects in the early universe. Recent work has shown that, although relative motion of the two fluids is formally a second order effect in density, it has a dramatic impact on the formation and distribution of the first cosmic structures. Focusing on the gas content, we analyze the effect of relative velocity on the properties of halos over a wide range of halo masses and redshifts. We calculate accurately the linear evolution of the baryon and dark matter fluctuations, and quantify the resulting effect on halos based on an analytical formalism that has been carefully checked with simulations in the case with no relative velocity. We estimate the effect on the abundance of and gas fraction in early halos. We find that the relative velocity effect causes several changes: (i) the characteristic mass that divides gas-rich and gas-poor halos is increased by roughly an order of magnitude, from 2 10^4 Msun to about 2 10^5 Msun; (ii) this characteristic mass has a large scatter (full width at half maximum is ~ 1.5 10^5 Msun at z=20); (iii) the fraction of baryons in star-less gas minihalos is suppressed by a factor of 4 at z=20; (iv) the fraction of baryons in halos that can cool and form stars is suppressed by a factor of 1.5 at z=20; and (v) there are enhanced spatial variations of these various fractions.
In this letter we provide a reformulation of the strong cosmic censor conjecture taking into account recent results on Malament--Hogarth space-times. We claim that the strong version of the cosmic censor conjecture can be formulated by postulating that a physically relevant space-time is either globally hyperbolic or possesses the Malament--Hogarth property. But it is known that a Malament--Hogarth space-time in principle is capable for performing non-Turing computations such as checking consistency of ZFC set theory. In this way we get an intimate conjectured link between the cosmic censorship scenario and computability theory.
For $v\equiv 1$ or 3 (mod 6), maximum partial triple systems on $v$ points are Steiner triple systems, STS($v$)s. The 80 non-isomorphic STS(15)s were first enumerated around 100 years ago, but the next case for Steiner triple systems was unresolved until around 2004 when it was established that there are precisely 11084874829 non-isomorphic STS(19)s. In this paper we complete enumeration of non-isomorphic maximum partial triple systems for $v\le 19$. It is shown that there are 35810097 systems on 17 points and 47744568 on 16 points. We also establish that there are precisely 157151 non-isomorphic pairwise balanced designs, PBD($17,\{3,5\}$)s, having a single block of size 5. Structural properties of these systems are determined, including their automorphism groups, and the numbers of Pasch configurations, mitres and Fano planes contained in them. The systems themselves are available from the authors.
We consider twisted zeta series of several variables associated to polynomials of several variables. Thanks to a totally new method (exchange lemma) we calculate the values at vectors formed of negative integers.After transformation of the formula we obtained, we make p-adic interpolation.   -----   Nous considerons des series zetas multivariables associees a des polynomes de plusieurs variables. Grace a une methode totalement nouvelle (dite du lemme d'echange) nous calculons les valeurs aux T-uplets d'entiers negatifs. Apres transformation des formules ainsi obtenues nous faisons l'interpolation p-adique.
There is a consensus in the literature that starburst galaxies are triggered by inter- action events. However, it remains an open question as to what extent both merging and non-merging interactions have in triggering starbursts? In this study, we make use of the Illustris simulation to test how different triggering mechanisms can effect starburst events. We examine star formation rate, colour and environment of starburst galaxies to determine if this could be why we witness a bimodality in post-starburst populations within observational studies. Further, we briefly test the extent of quenching due to AGN feedback. From Illustris, we select 196 starburst galaxies at z = 0.15 and split them into post-merger and pre-merger/harassment driven starburst samples. We find that 55% of this sample not undergone a merger in the past 2 Gyr. Both of our samples are located in low-density environments within the filament regions of the cosmic web, however we find that pre-merger/harassment driven starburst are in higher density environments than post-merger driven starbursts. We also find that pre-merger/harassment starbursts are redder than post-merger starbursts, this could be driven by environmental effects. Both however, produce nuclear starbursts of comparable strengths.