ShantanuT01/DACTYL-Pretraining huggingface dataset:
We show that the claims expressed in the Comment arXiv:0810.3244v1 by R.S. Decca et al against our paper, D.A.R. Dalvit and S.K. Lamoreaux, Phys. Rev. Lett. {\bf 101}, 163203 (2008), are wrong and manifestly inconsistent with basic principles of statistical physics.
The pressure dependence of the Curie temperature T$_{C}(P)$ in La$_{0.75}$Ca$_{0.25}$MnO$_{3}$ was determined by neutron diffraction up to 8 GPa, and compared with the metallization temperature T$_{IM}(P)$ \cite{irprl}. The behavior of the two temperatures appears similar over the whole pressure range suggesting a key role of magnetic double exchange also in the pressure regime where the superexchange interaction is dominant. Coexistence of antiferromagnetic and ferromagnetic peaks at high pressure and low temperature indicates a phase separated regime which is well reproduced with a dynamical mean-field calculation for a simplified model. A new P-T phase diagram has been proposed on the basis of the whole set of experimental data.
In investigations of the emergence of classicality from quantum theory, a useful step is the construction of quantum operators corresponding to the classical notion that the system resides in a region of phase space. The simplest such constructions, using coherent states, yield operators which are approximate projection operators -- their eigenvalues are approximately equal to 1 or 0. Such projections may be shown to have close to classical behaviour under time evolution and these results have been used to prove some useful results about emergent classicality in the decoherent histories approach to quantum theory. Here, we show how to use the eigenstates of a suitably chosen Hamiltonian to construct exact projection operators which are localized on regions of phase. We elucidate the properties of such operators and explore their time evolution. For the special case of the harmonic oscillator, the time evolution is particularly simple, and we find sets of phase space localized histories which are exactly decoherent for any initial state and have probability 1 for classical evolution. These results show how approximate decoherence of histories and classical predictability for phase space histories may be made exact in certain cases.
We quantify the rate of double diffractive Higgs/dijet production at $pp$ (or $p\bar{p}$) colliders. The suppression due to QCD bremsstrahlung is calculated perturbatively up to single $\log$ accuracy. The survival probability of the rapidity gaps is discussed. A first comparison with experiment is made.
We continue study of the connection of classical limit of integrable asymptotically free field theory to the finite-gap solutions of classical integrable equations. In the limit the momenta of particles turn into the moduli of Riemann surfaces while their isotopic structure is related to the period lattices. In this paper we explain that the classical limit of the local operators can be understood as a measure induced on the phase space by embedding into the projective space of "classical fields".
A family X of sets is said to be intersecting if any two members of X have non-empty intersection. It is a well-known and simple fact that an intersecting family of subsets of [n]={1,2,...,n} can contain at most 2^(n-1) sets. Katona, Katona and Katona ask the following question. Suppose instead a family X of subsets of [n] satisfies |X|=2^(n-1)+i for some fixed i>0. Create a new family X_p by choosing each member of X independently with some fixed probability p. How do we choose X to maximize the probability that X_p is intersecting? They conjecture that there is a nested sequence of optimal families for i=1, 2, ..., 2^(n-1). In this paper, we show that the families [n]^(\ge r)={A\subset[n]:|A|\ge r} are optimal for the appropriate values of i, thereby proving the conjecture for this sequence of values. Moreover, we show that for intermediate values of i there exist optimal families lying between those we have found. It turns out that the optimal families we find simultaneously maximize the number of intersecting subfamilies of every possible order. Standard compression techniques appear inadequate to solve the problem as they do not preserve intersection properties of subfamilies. Instead, our main tool is a novel compression method, together with a way of `compressing' subfamilies, which may be of independent interest.
Interstellar medium is turbulent and this induces relative motions of dust grains. We calculate relative velocities of charged grains in a partially ionized magnetized gas. We account for anisotropy of magnetohydrodynamic (MHD) turbulence, grain coupling with magnetic field, and the turbulence cutoff arising from the ambipolar drag. We obtain grain velocities for turbulence with parameters consistent with those in HI and dark clouds. Those velocities are smaller than those in earlier papers, where MHD effects were disregarded. Finally, we compare grain velocities arising from photoelectric emission, radiation pressure and thrusts from molecular hydrogen formation. We conclude that turbulence should prevent segregation of grains of different sizes.
We analyse the X-ray time-lags in the Narrow Line Seyfert 1 (NLS1) galaxy PG 1244+026 ($M_{\rm BH}\sim 10^7 M_{\rm sun}$, $L/L_{\rm Edd}\sim 1$). The time delay between the soft (0.3--0.7~keV) and harder (1.2--4.0~keV) variations shows shows the well established switch from hard lags at low frequencies to soft lags at high frequencies. The low frequency hard lags are qualitatively consistent with the propagation of fluctuations model, with some long-timescale response of the reflection component. The high frequency soft lag appears to extend over a wide frequency band, that we divide this into two narrow frequency ranges, and examine the lag as a function of energy for each of these. At high frequencies the soft excess emission is delayed with respect to the harder energy bands, without any corresponding strong, hard X-ray reflection signature. At even higher frequencies a soft lag is seen at the softest energies, as well as tentative evidence for an iron K$\alpha$ reverberation signal. These results point to the importance of reprocessing as well as reflection in determining the lags in NLS1s.
We address a primary question regarding the physical mechanism that triggers the energy release and initiates the onset of eruptions in the magnetar magnetosphere. A self-consistent stationary, axisymmetric model of the magnetar magnetosphere is constructed based on a force-free magnetic field configuration which contains a helically twisted force-free flux rope. Given the complex multipolar magnetic fields at the magnetar surface, we also develop a convenient numerical scheme to solve the GS equation. Depending on the surface magnetic field polarity, there exist two kinds of magnetic field configurations, inverse and normal. For these two kinds of configurations, variations of the flux rope equilibrium height in response to gradual surface physical processes, such as flux injections and crust motions, are carefully examined. We find that equilibrium curves contain two branches, one represents a stable equilibrium branch, the other an unstable equilibrium branch. As a result, the evolution of the system shows a catastrophic behavior: when the magnetar surface magnetic field evolves slowly, the height of flux rope would gradually reach a critical value beyond which stable equilibriums can no longer be maintained. Subsequently the flux rope would lose equilibrium and the gradual quasi-static evolution of the magnetar magnetosphere will be replaced by a fast dynamical evolution. In addition to flux injections, the relative motion of active regions would give rise to the catastrophic behavior and lead to magnetic eruptions as well. We propose that a gradual process could lead to a sudden release of magnetosphere energy on a very short dynamical timescale, without being initiated by a sudden fracture in the crust of the magnetar. Some implications of our model are also discussed.
A normal-fluid component varying as T$^{2}$ is observed at very low temperatures in superfluid $^4$He and $^3$He-$^4$He mixture films adsorbed in alumina powder. The normal fluid appears to arise from thermally excited third sound that has one-dimensional propagation characteristics. A Landau model of third sound excitations in an infinite cylindrical pore by Saam and Cole provides good agreement with the experimental measurements over a wide range of $^4$He and $^3$He coverages. However, it is unclear why the powder substrate can be modeled as having cylindrical pores.
Zero-Shot Learning (ZSL) is typically achieved by resorting to a class semantic embedding space to transfer the knowledge from the seen classes to unseen ones. Capturing the common semantic characteristics between the visual modality and the class semantic modality (e.g., attributes or word vector) is a key to the success of ZSL. In this paper, we propose a novel encoder-decoder approach, namely Latent Space Encoding (LSE), to connect the semantic relations of different modalities. Instead of requiring a projection function to transfer information across different modalities like most previous work, LSE per- forms the interactions of different modalities via a feature aware latent space, which is learned in an implicit way. Specifically, different modalities are modeled separately but optimized jointly. For each modality, an encoder-decoder framework is performed to learn a feature aware latent space via jointly maximizing the recoverability of the original space from the latent space and the predictability of the latent space from the original space. To relate different modalities together, their features referring to the same concept are enforced to share the same latent codings. In this way, the common semantic characteristics of different modalities are generalized with the latent representations. Another property of the proposed approach is that it is easily extended to more modalities. Extensive experimental results on four benchmark datasets (AwA, CUB, aPY, and ImageNet) clearly demonstrate the superiority of the proposed approach on several ZSL tasks, including traditional ZSL, generalized ZSL, and zero-shot retrieval (ZSR).
We define tensors, corresponding to cubic polynomials, which have the same exponent $\omega$ as the matrix multiplication tensor. In particular, we study the symmetrized matrix multiplication tensor $sM_n$ defined on an $n\times n$ matrix $A$ by $sM_n(A)=trace(A^3)$. The use of polynomials enables the introduction of additional techniques from algebraic geometry in the study of the matrix multiplication exponent $\omega$.
When a mathematical or computational model is used to analyse some system, it is usual that some parameters resp.\ functions or fields in the model are not known, and hence uncertain. These parametric quantities are then identified by actual observations of the response of the real system. In a probabilistic setting, Bayes's theory is the proper mathematical background for this identification process. The possibility of being able to compute a conditional expectation turns out to be crucial for this purpose. We show how this theoretical background can be used in an actual numerical procedure, and shortly discuss various numerical approximations.
Let $\Gamma\subseteq\mathrm{PSL}_{2}(\mathbb{R})$ be a Fuchsian subgroup of the first kind acting on the upper half-plane $\mathbb{H}$. Consider the $d$-dimensional space of cusp forms $\mathcal{S}_{k}^{\Gamma}$ of weight $2k$ for $\Gamma$, and let $\{f_{1},\ldots,f_{d}\}$ be an orthonormal basis of $\mathcal{S}_{k}^{\Gamma}$ with respect to the Petersson inner product. In this paper we show that the sup-norm of the quantity $S_{k}^{\Gamma}(z):=\sum_{j=1}^{d}| f_{j}(z)|^{2}\,\mathrm{Im}(z)^{2k}$ is bounded as $O_{\Gamma}(k)$ in the cocompact setting, and as $O_{\Gamma}(k^{3/2})$ in the cofinite case, where the implied constants depend solely on $\Gamma$. We also show that the implied constants are uniform if $\Gamma$ is replaced by a subgroup of finite index.
The observed spectral energy distributions of five GeV-selected narrow-line Seyfert 1 (NLS1) galaxies are fitted with a model including the radiation ingredients from the relativistic jet, the accretion disk, and the corona. We compare the properties of these GeV NLS1 galaxies with flat spectrum radio quasars (FSRQs), BL Lacertae objects (BL Lacs) and radio-quiet (RQ) Seyfert galaxies, and explore possible hints for jet-disk/corona connection. Our results show that the radiation physics and the jet properties of the GeV NLS1 galaxies resemble that of FSRQs. The luminosity variations of PMN J0948+0022 and 1H 0323+342 at GeV band is tightly correlated with the beaming factor ({\delta}), similar to that observed in FSRQ 3C 279. The accretion disk luminosities and the jet powers of the GeV NLS1 galaxies cover both the ranges of FSRQs and BL Lacs. With detection of bright corona emission in 1H 0323+342, we show that the ratio of the corona luminosity (L_corona) to the accretion disk luminosity (L_d) is marginally within the high end of this ratio distribution for a RQ Seyfert galaxy sample, and the variation of jet luminosity may connect with Lcorona. However, it is still unclear whether a system with a high L_corona/L_d ratio prefers to power a jet.
We propose that the concept of liquids characterized by a given locally preferred structure (LPS) could help in understanding the observed phenomenon of polyamorphism. ``True polyamorphism'' would involve the competition between two (or more) distinct LPS, one favored at low pressure because of its low energy and one favored at high pressure because of its small specific volume, as in tetrahedrally coordinated systems. ``Apparent polyamorphism'' could be associated with the existence of a poorly crystallized defect-ordered phase with a large unit cell and small crystallites, which may be illustrated by the metastable glacial phase of the fragile glassformer triphenylphosphite; the apparent polyamorphism might result from structural frustration, i. e., a competition between the tendency to extend the LPS and a global constraint that prevents tiling of the whole space by the LPS.
One-dimensional model of a system where first-order phase transition occurs is examined in the present paper. It is shown that basic properties of the phenomenon, such as a well defined temperature of transition, are caused both by existence of a border between the phases and the fact that only in the vicinity of that border it is possible for molecules to change their phase. Not only the model is introduced and theoretical analysis of its properties is made but also the results of Monte Carlo simulations are presented together with the results of numerical calculation of the distribution of energy levels of the system.
We introduce the notion of filtered representations of quivers, which is related to usual quiver representations, but is a systematic generalization of conjugacy classes of $n\times n$ matrices to (block) upper triangular matrices up to conjugation by invertible (block) upper triangular matrices. With this notion in mind, we describe the ring of invariant polynomials for interesting families of quivers, namely, finite $ADE$-Dynkin quivers and affine type $\widetilde{A}$-Dynkin quivers. We then study their relation to an important and fundamental object in representation theory called the Grothendieck-Springer resolution, and we conclude by stating several conjectures, suggesting further research.
We show that a source-to-detector distance of 2540 km offers multiple advantages for a low energy neutrino factory with a detector that can identify muon charge. At this baseline, for any neutrino hierarchy, the wrong-sign muon signal is almost independent of CP violation and $\theta_{13}$ in certain energy ranges. This reduces the uncertainties due to these parameters and allows the identification of the hierarchy in a clean way. In addition, part of the muon spectrum is also sensitive to the CP violating phase and $\theta_{13}$, so that the same setup can be used to probe these parameters as well.
Topological insulators display unusual light-matter interactions due to the helical nature of surface electronic states. We study the near-field interaction of light propagating in an optical fiber with crystals of Sb2Te3, a 3D topological insulator (TI), and observe a large apparent Faraday rotation. The origin of this unexpected polarization rotation in the optical fiber is attributed to a magneto-optical Kerr effect at the TI-fiber interface. We show that the combined effects of time-reversal symmetry breaking, which arises from Zeeman coupling of the electromagnetic field with the surface electrons of the TI, and inversion symmetry breaking of optical excitations, which arises from the exponential decay of the evanescent light across the TI crystal, are central to realizing this giant polarization rotation. Our work demonstrates a facile approach for realizing large magneto-optical effects without any magnetic fields by exploiting the unique physics of light-matter interactions at TI surfaces.
To advance the use of thermally-activated magnetic materials in device applications it is necessary to examine their behaviour on the localised scale in operando conditions. Equi-atomic FeRh undergoes a magnetostructural transition from an antiferromagnetic (AF) to a ferromagnetic (FM) phase above room temperature (~ 75 to 105 {\deg}C) and hence is considered a very desirable material for the next generation of novel nanomagnetic or spintronic devices. For this to be realised, we must fully understand the intricate details of AF to FM transition and associated FM domain growth on the scale of their operation. Here we combine in-situ heating with a comprehensive suite of advanced transmission electron microscopy techniques to investigate directly the magnetostructural transition in nano-scale FeRh thin films. Differential phase contrast imaging visualizes the stages of FM domain growth in both cross-sectional and planar FeRh thin films as a function of temperature. Small surface FM signals are also detected due to interfacial strain with the MgO substrate and Fe deficiency after HF etching of the substrate, providing a directional bias for FM domain growth. Our work provides high resolution imaging and quantitative measurements throughout the transition, which were previously inaccessible, and offers new fundamental insight into their potential use in magnetic devices.
A recent comparison by Merritt et al. 2020 of simulated and observed Milky Way-mass galaxies has identified a significant tension between the outskirts ($r>20\kpc$) of the stellar halos in simulated and observed galaxies. Using observations from the Dragonfly telescope and simulated galaxies from the Illustris-TNG100 project, Merritt et al. 2020 finds that the outskirts of stellar halos in simulated galaxies have surface densities $1-2$ dex higher than observed galaxies. In this paper, we compare two suites of 15 simulated Milky Way-like galaxies, each drawn from the same initial conditions, simulated with the same hydrodynamical code, but with two different models for feedback from supernovae. We find that the MUGS simulations, which use an older ``delayed-cooling'' model for feedback, also produce too much stellar mass in the outskirts of the halo, with median surface densities well above observational constraints. The MUGS2 simulations, which instead use a new, physically-motivated ``superbubble'' model for stellar feedback, have $1-2$ dex lower outer stellar halo masses and surface densities. The MUGS2 simulations generally match both the median surface density profile as well as the scatter in stellar halo surface density profiles seen in observed stellar halos. We conclude that there is no ``missing outskirts'' problem in cosmological simulations, provided that supernova feedback is modelled in a way that allows it to efficiently regulate star formation in the low-mass progenitor environments of stellar halo outskirts.
Traffic-light modelling is a complex task, because many factors have to be taken into account. In particular, capturing all traffic flows in one model can significantly complicate the model. Therefore, several realistic features are typically omitted from most models. We introduce a mechanism to include pedestrians and focus on situations where they may block vehicles that get a green light simultaneously. More specifically, we consider a generalization of the Fixed-Cycle Traffic-Light (FCTL) queue. Our framework allows us to model situations where (part of the) vehicles are blocked, e.g. by pedestrians that block turning traffic and where several vehicles might depart simultaneously, e.g. in case of multiple lanes receiving a green light simultaneously. We rely on probability generating function and complex analysis techniques which are also used to study the regular FCTL queue. We study the effect of several parameters on performance measures such as the mean delay and queue-length distribution.
In this article we study the well-posedness (uniqueness and existence of solutions) of nonlinear elliptic Partial Differential Equations (PDEs) on a finite graph. These results are obtained using the discrete comparison principle and connectivity properties of the graph. This work is in the spirit of the theory of viscosity solutions for PDEs.   The equations include the graph Laplacian, the $p$-Laplacian, the Infinity Laplacian, the Mean Curvature equation, and the Eikonal operator on the graph.
To construct actions for describing superbranes propagating in AdS x S superbackgrounds we propose a coset space realization of these superbackgrounds which results in a short polynomial fermionic dependence (up to the sixth power in Grassmann coordinates) of target superspace supervielbeins and superconnections. Gauge fixing kappa-symmetry in a way compatible with a static brane solution further reduces the fermionic dependence down to the fourth power. Subtleties of consistent gauge fixing worldvolume diffeomorphisms and kappa-symmetry of the superbrane actions are discussed.
An analog of the $j=1/2$ Feynman-Dyson propagator is presented in the framework of the $j=1$ Weinberg's theory. The basis for this construction is the concept of the Weinberg field as a system of four field functions differing by parity and by dual transformations.
Contaminants such as dust, dirt and moisture adhering to the camera lens can greatly affect the quality and clarity of the resulting image or video. In this paper, we propose a video restoration method to automatically remove these contaminants and produce a clean video. Our approach first seeks to detect attention maps that indicate the regions that need to be restored. In order to leverage the corresponding clean pixels from adjacent frames, we propose a flow completion module to hallucinate the flow of the background scene to the attention regions degraded by the contaminants. Guided by the attention maps and completed flows, we propose a recurrent technique to restore the input frame by fetching clean pixels from adjacent frames. Finally, a multi-frame processing stage is used to further process the entire video sequence in order to enforce temporal consistency. The entire network is trained on a synthetic dataset that approximates the physical lighting properties of contaminant artifacts. This new dataset and our novel framework lead to our method that is able to address different contaminants and outperforms competitive restoration approaches both qualitatively and quantitatively.