ShantanuT01/DACTYL-Pretraining huggingface dataset:
Given a probability density $P({\bf x}|{\boldsymbol \lambda})$, where $\bf x$ represents continuous degrees of freedom and $\lambda$ a set of parameters, it is possible to construct a general identity relating expectations of observable quantities, which is a generalization of the equipartition theorem in Thermodynamics.   In this work we explore some of the consequences of this relation, both in the context of sampling distributions and Bayesian posteriors, and how it can be used to extract some information without the need for explicit calculation of the partition function (or the Bayesian evidence, in the case of posterior expectations). Together with the general family of fluctuation theorems it constitutes a powerful tool for Bayesian/MaxEnt problems.
A common approach for the numerical simulation of wave propagation on a spatially unbounded domain is to truncate the domain via an artificial boundary, thus forming a finite computational domain with an outer boundary. Absorbing boundary conditions must then be specified at the boundary such that the resulting initial-boundary value problem is well posed and such that the amount of spurious reflection is minimized. In this article, we review recent results on the construction of absorbing boundary conditions in General Relativity and their application to numerical relativity.
A partial-wave analysis of all antiproton-proton scattering data below 925 MeV/c antiproton laboratory momentum is presented. The method used is adapted from the Nijmegen phase-shift analyses of pp and np scattering data. The Nijmegen 1993 antiproton-proton database, consisting of 3646 antiproton-proton scattering data, is presented and discussed. The best fit to this database results in chi^2_min/Ndata = 1.043. The pseudovector coupling constant of the charged pion to nucleons is determined to be (f_c)^2 = 0.0732(11) at the pion pole, where the error is statistical.
Optical searches assisted by the field of a laser pulse might allow for exploring a variety of not yet detected dark matter candidates such as hidden-photons and scalar minicharged particles. These hypothetical degrees of freedom may be understood as a natural consequence of extensions of the Standard Model incorporating a hidden $\rm U(1)$-gauge sector. In this paper, we study the effects induced by both candidates on the propagation of a probe electromagnetic waves in the vacuum polarized by a long laser pulse of moderate intensity, this way complementing our previous study [JHEP \textbf{06}, $177$ ($2015$)]. We describe how the absence of a spin in the scalar charged carriers modifies the photon-paraphoton oscillations as compared with a fermionic minicharge model. In particular, we find that the regime close to their lowest threshold mass might provide the most stringent upper limit for minicharged scalars. The pure-laser based experiment investigated here could allow 23for excluding a sector in the parameter space of the particles which has not been experimentally ruled out by setups driven by dipole magnets. We explain how the sign of the ellipticity and rotation of the polarization plane acquired by a probe photon--in combination with their dependencies on the pulse parameters--can be exploited to elucidate the quantum statistics of the charge carriers.
We show that a KSVZ axion with a decay constant in the phenomenologically allowed range can be obtained in certain $E_8\times E_8$ heterotic string models. These models have an enhanced symmetry locus in the moduli space, and a non-universal, Kahler moduli dependent Fayet-Iliopoulos term which vanishes at this locus. Close to this locus the Fayet-Iliopoulos term is small and can lead to an axion decay constant significantly lower than the string scale. In this way, the no-go arguments of Svrcek and Witten, which are based on a universal, dilaton-dependent Fayet-Iliopoulos term, can be avoided. The relevant axion originates from phases of bundle moduli which correspond to deformations away from the enhanced symmetry locus. We construct an explicit example, based on a heterotic line bundle standard model, with all the required ingredients.
We propose a model for an anisotropic dark energy star where we assume that the radial pressure exerted on the system due to the presence of dark energy is proportional to the isotropic perfect fluid matter density. We discuss various physical features of our model and show that the model satisfies all the regularity conditions and stable as well as singularity-free.
In my PhD thesis I show the existence of global-in-time weak solutions for a Navier-Stokes fluid interacting with a linearly elastic shell of Koiter type. This is achieved by the introduction of a new method for showing the compactness of bounded sequences of approximate weak solutions. This method might be of general interest in the study of fluid dynamical problems involving a free boundary. There is no damping term involved in the shell equations.
This paper reviews the dust content of the high redshift (z > 2) universe. Studies of the various "species" in the high-z "zoo" show that almost all have strong evidence for containing dust. The one exception, where the evidence is not yet convincing, is in quasar absorption line systems, particularly those with low column density. These may not even be associated with galaxies. The high-z galaxy types which do show evidence for dust are all strongly star forming. Hence, as seen locally, star formation and dust in the distant universe are also strongly correlated. It is beyond debate that star formation at z ~ 3 is dominated by dusty systems who emit most of their bolometric flux in the rest-frame FIR. What is not clear is whether these systems are totally invisible at shorter wavelengths, or whether a large fraction are visible in the rest-frame UV as Lyman Break Galaxies. The issue may not be settled until the sub-mm background is definitively resolved.
Photon breeding in relativistic jets involves multiplication of high-energy photons propagating from the jet to the external environment and back with the conversion into electron-positron pairs. The exponential growth of the energy density of these photons is a super-critical process powered by the bulk energy of the jet. The efficient deceleration of the jet outer layers creates a structured jet morphology with the fast spine and slow sheath. In initially fast and high-power jets even the spine can be decelerated efficiently leading to very high radiative efficiencies of conversion of the jet bulk energy into radiation. The decelerating, structured jets have angular distribution of radiation significantly broader than that predicted by a simple blob model with a constant Lorentz factor. This reconciles the discrepancy between the high Doppler factors determined by the fits to the spectra of TeV blazars and the low apparent velocities observed at VLBI scales as well as the low jet Lorentz factors required by the observed statistics and luminosity ratio of Fanaroff-Riley I radio galaxies and BL Lac objects. Photon breeding produces a population of high-energy leptons in agreement with the constraints on the electron injection function required by spectral fits of the TeV blazars. Relativistic pairs created outside the jet and emitting gamma-rays by inverse Compton process might explain the relatively high level of the TeV emission from the misaligned jet in the radio galaxies. The mechanism reproduces basic spectral features observed in blazars including the blazar sequence (shift of the spectral peaks towards lower energies with increasing luminosity). The mechanism is very robust and can operate in various environments characterised by the high photon density.
According to the collapsar model, gamma-ray bursts are thought to be produced in shocks that occur after the relativistic jet has broken free from the stellar envelope. If the mass density of the collimated outflow is less than that of the stellar envelope, the jet will then be surrounded by a cocoon of relativistic plasma. This material would itself be able to escape along the direction of least resistance, which is likely to be the rotation axis of the stellar progenitor, and accelerate in approximately the same way as an impulsive fireball. We discuss how the properties of the stellar envelope have a decisive effect on the appearance of a cocoon propagating through it. The relativistic material that accumulated in the cocoon would have enough kinetic energy to substantially alter the structure of the relativistic outflow, if not in fact provide much of the observed explosive power. Shock waves within this plasma can produce gamma-ray and X-ray transients, in addition to the standard afterglow emission that would arise from the deceleration shock of the cocoon fireball.
We compare the large scale galaxy clustering in the new SDSS early data release (EDR) with the clustering in the APM Galaxy Survey. We cut out pixel maps (identical in size and shape) from the SDSS and APM data to allow a direct comparison of the clustering. Here we concentrate our analysis on an equatorial SDSS strip in the South Galactic Cap (EDR/SGC) with 166 deg^2, 2.5 wide and 65 degrees long. Only galaxies with Petrosian magnitudes 16.8 <g'<19.8 are included to match the surface density of the 17< b_J<20 APM pixel maps (median depth of 400 Mpc/h). Both the amplitude and shape of the angular 2-point function and variance turn out to be in very good agreement with the APM on scales smaller than 2 degrees (ie 15 Mpc/h). The 3-point function and skewness are also in excellent agreement within a 90% confidence level. On one hand these results illustrate that the EDR data and SDSS software pipelines, work well and are suitable to do analysis of large scale clustering. On the other hand it confirms that large scale clustering analysis is becoming "repeatable" and therefore that our conclusions for structure formation models seem to stand on solid scientific grounds.
We present a detailed morphological analysis of the galaxy populations in the first two clusters to be completed in an extensive observational study of nine high-redshift clusters of galaxies (Oke, Postman & Lubin 1998). These two clusters, CL0023+0423 and CL1604+4304, are at redshifts of z = 0.84 and z = 0.90, respectively. The morphological studies are based on high-angular resolution imagery taken with WFPC2 aboard the Hubble Space Telescope. These data are combined with deep, ground-based BVRI photometry and spectra taken with the Keck 10-meter telescopes. Based on these observations, CL0023+0423 has a galaxy population which is more similar to groups of galaxies and the field. This system is almost completely dominated by spiral galaxies. CL1604+4304, however, has a morphological composition which is more typical of a normal, present-day cluster; early-type galaxies comprise approximately 76% of all galaxies brighter than M_V = -19.0 + 5 log h in the central 0.5 h^{-1} Mpc. The ratio of S0 galaxies to ellipticals in this cluster is 1.7 +/- 0.9, consistent with local cluster populations. The morphological results support the conclusions of the dynamical analysis presented in the second paper of this series (Postman, Lubin & Oke 1998). CL0023+0423 consists of two galaxy groups which are separated by approximately 2900 km/s in radial velocity. On the other hand, CL1604+4304 has a morphological composition, velocity dispersion, and implied mass which are consistent with an Abell richness class 2 or 3 cluster.
We suggest that low-mass compact objects (hadron stars, quark stars) with $M<1 M_{\odot}$ can appear only due to fragmentation of rapidly rotating proto-neutron stars. Such low-mass stars receive large kicks due to an explosion of a lighter companion in a pair of fragments, or due to dynamical ejection of one of the lighter components in the case when three bodies are formed.   As far as low-mass compact objects are expected to be slowly cooling in all popular models of thermal evolution possible candidates are expected to be found among hot high velocity sources.
We report a complete 2mm spectral line survey (130-170 GHz) taken with the NRAO 12m Telescope between 1993 and 1995 toward the following sources: Sgr B2N, Sgr B2OH, IRC +10 216, Orion (KL), Orion-S, W51M, and W3(IRS5).   Until very recently, this project was entirely the work of B. E. Turner. He wrote the original proposal, given below without changes or updates, and did all of the observing. B.E. Turner has fallen seriously ill and can no longer continue to work on the analysis of these data. The notes that follow the proposal give further information about the project and important information for users of these data.   The data are distributed using the Spectral Line Search Engine (SLiSE) developed by A. J. Remijan and M. J. Remijan. SLiSE is a data display tool that will contain all the fully reduced and calibrated archived data taken as part of this 2mm survey. SLiSE is fast, easy to use, and contains the necessary functionality to display the data taken from spectral line searches. For example, SLiSE contains functions to overlay possible molecule identifications based on a current line catalog as well as overlaying H and He recombination lines. It is a Java-based applet, so it is platform independent and easily accessed online. The only caveat is that SLiSE was built using Java 1.5, so an update to the user's Java may be necessary.   We request users of these data to give B.E. Turner and this work the appropriate citation and credit.
We point out that the observed CP violation in Bd - bar{Bd} mixing, taking into account the measured ratio Delta Md / Delta Ms, the recently improved lattice value of the non-perturbative parameter BK and an additional effective suppression factor kappa_epsilon ~= 0.92 in epsilon_K neglected sofar in most analyses, may be insufficient to describe the measured value of epsilon_K within the Standard Model (SM), thus hinting at new CP violating contributions to the K - bar{K} and/or Bd - bar{Bd} systems. Furthermore, assuming that Delta Md / Delta Ms is SM-like, the signs and the magnitudes of new physics effects in epsilon_K and in the CP asymmetries S_{psi Ks} and S_{psi phi} may turn out to be correlated. For example, in a scenario with new CP-phases in Bd and Bs mixings being approximately equal and negative, a common new phase ~= - 5 degrees could remove the tension between epsilon_K and S_{psi Ks} present in the SM and simultaneously accommodate, at least partly, the recent claim of S_{psi phi} being much larger than the SM expectation. We emphasize the importance of precise determinations of Vcb, BK, FK and xi_s, to which the parameter epsilon_K and its correlation with the CP violation in the Bd - bar{Bd} system are very sensitive.
We examine the scatter of the relation between stellar mass and stellar metallicity for cluster dwarf galaxies in the cosmological simulation Illustris. The mass-metallicity relation exhibits the smallest intrinsic scatter at the galaxies' times of peak stellar mass, suggesting stellar mass stripping to be the primary effect responsible for the rather broad relation at present. However, for about 40% of galaxies in the high-metallicity tail of the relation, we find mass stripping to coincide with an increased enrichment of stellar metallicity, possibly caused by the stripping of low-metallicity stars in the galaxy outskirts.
The electric field (EF) effect on the magnetic domain structure of a Pt/Co system was studied, where an EF was applied to the top surface of the Co layer. The width of the maze domain was significantly modified by the application of the EF at a temperature slightly below the Curie temperature. After a detailed analysis, a change in the exchange stiffness induced by the EF application was suggested to dominate the modulation of the domain width observed in the experiment. The accumulation of electrons at the surface of the Co layer resulted in an increase of the exchange stiffness and the Curie temperature. The result was consistent with the recent theoretical prediction.
I present a way to visualize the concept of curved spacetime. The result is a curved surface with local coordinate systems (Minkowski Systems) living on it, giving the local directions of space and time. Relative to these systems, special relativity holds. The method can be used to visualize gravitational time dilation, the horizon of black holes, and cosmological models. The idea underlying the illustrations is first to specify a field of timelike four-velocities. Then, at every point, one performs a coordinate transformation to a local Minkowski system comoving with the given four-velocity. In the local system, the sign of the spatial part of the metric is flipped to create a new metric of Euclidean signature. The new positive definite metric, called the absolute metric, can be covariantly related to the original Lorentzian metric. For the special case of a 2-dimensional original metric, the absolute metric may be embedded in 3-dimensional Euclidean space as a curved surface.
Shift operation is an efficient alternative over depthwise separable convolution. However, it is still bottlenecked by its implementation manner, namely memory movement. To put this direction forward, a new and novel basic component named Sparse Shift Layer (SSL) is introduced in this paper to construct efficient convolutional neural networks. In this family of architectures, the basic block is only composed by 1x1 convolutional layers with only a few shift operations applied to the intermediate feature maps. To make this idea feasible, we introduce shift operation penalty during optimization and further propose a quantization-aware shift learning method to impose the learned displacement more friendly for inference. Extensive ablation studies indicate that only a few shift operations are sufficient to provide spatial information communication. Furthermore, to maximize the role of SSL, we redesign an improved network architecture to Fully Exploit the limited capacity of neural Network (FE-Net). Equipped with SSL, this network can achieve 75.0% top-1 accuracy on ImageNet with only 563M M-Adds. It surpasses other counterparts constructed by depthwise separable convolution and the networks searched by NAS in terms of accuracy and practical speed.
We give factorizations for weighted spanning tree enumerators of Cartesian products of complete graphs, keeping track of fine weights related to degree sequences and edge directions. Our methods combine Kirchhoff's Matrix-Tree Theorem with the technique of identification of factors.
We consider the production of heavy-quark pairs in the collisions of polarized and unpolarized on-shell photons and present, in analytic form, the fully integrated total cross sections for total photon spins $J_z=0, \pm 2$ at next-to-leading-order in QCD. Phenomenological applications include $b\bar b$ production, which represents an irreducible background to standard-model intermediate-mass Higgs-boson production, as well as $t\bar t$ production.
We show that geodesics in the upper half-plane attached to a maximal split torus or a real quadratic torus in $GL_{2, \mathbf{Q}}$ are the only irreducible algebraic curves whose image via the $j$-invariant is contained in an algebraic curve.
Frankl and F\"uredi (1989) conjectured that the $r$-graph with $m$ edges formed by taking the first $m$ sets in the colex ordering of ${\mathbb N}^{(r)}$ has the largest graph-Lagrangian of all $r$-graphs with $m$ edges. In this paper, we establish some bounds for graph-Lagrangians of some special $r$-graphs that support this conjecture.
It is well known that high energy data alone do not discriminate between asymptotic $\ln s$ and $\ln^2s$ behavior of $pp$ and $\bar pp$ cross sections. By exploiting high quality low energy data, analyticity resolves this ambiguity in favor of cross sections that grow asymptotically as $\ln^2s$. We here show that two methods for incorporating the low energy data into the high energy fits give numerically identical results and yield essentially identical tightly constrained values for the LHC cross section. The agreement can be understood as a new analyticity constraint derived as an extension of a Finite Energy Sum Rule.
We present results of ASCA deep exposure observations of the hardest X-ray source discovered in the ASCA Large Sky Survey (LSS) project, designated as AX J131501+3141. We extract its accurate X-ray spectrum, taking account of the contamination from a nearby soft source (AX J131502+3142), separated only by 1'. AX J131501+3141 exhibits a large absorption of NH = (6 +4 -2)x 10^22 H/cm^2 with a photon index \Gamma = 1.5 +0.7 -0.6. The 2--10 keV flux was about 5 x 10^-13 erg/s/cm^2 and was time variable by a factor of 30% in 0.5 year. From the highly absorbed X-ray spectrum and the time variability, as well as the results of the optical follow-up observations (Akiyama et al. 1998, astro-ph/9801173), we conclude that AX J131501+3141 is a type 2 Seyfert galaxy. Discovery of such a low flux and highly absorbed X-ray source could have a significant impact on the origin of the cosmic X-ray background.
Temperature dependencies of magnetic susceptibility in a trigonal single crystal of erbium aluminum borate were measured in the temperature range of 2 - 15 K at the external field of 100 Oe applied along the second- and third-order crystallographic axes. Analysis of the experimental data allows to identify the Van Vleck contribution to the susceptibility. The influence of spin correlations on the magnetic susceptibility has been identified. It has been estimate the negative paramagnetic Curie-Weiss temperature.
We carried out a finite-size scaling analysis of the restricted solid-on-solid version of a recently introduced growth model that exhibits a roughening transition accompanied by spontaneous symmetry breaking. The dynamic critical exponent of the model was calculated and found to be consistent with the universality class of the directed percolation process in a symmetry-broken phase with a crossover to Kardar-Parisi-Zhang behavior in a rough phase. The order parameter of the roughening transition together with the string order parameter was calculated, and we found that the flat, gapped phase is disordered with an antiferromagnetic spin-fluid structure of kinks, although strongly dominated by the completely flat configuration without kinks. A possible interesting extension of the model is mentioned.
We study the totally asymmetric exclusion process (TASEP) on a finite one-dimensional lattice with open boundaries, i.e., in contact with two reservoirs at different potentials. The total (time-integrated) current through the system is a random variable that scales linearly with time in the long time limit. We give a parametric representation for the generating function of the cumulants of the current, which is related to the large deviation function by Laplace transform. This formula is valid for all system sizes and for all values of the boundary coupling parameters.