ShantanuT01/DACTYL-Pretraining huggingface dataset:
We investigate the dark matter halos of 256 star-forming disc-like galaxies at $z\sim 1$ using the KMOS redshift one spectroscopic survey (KROSS). This sample covers the redshifts $0.6 \leq z \leq 1.04$, effective radii $0.69 \leq R_e [\mathrm{kpc}] \leq 7.76$, and total stellar masses $8.7 \leq log(M_{\mathrm{star}} \ [\mathrm{M_\odot}]) \leq 11.32$. We present a mass modelling approach to study the rotation curves of these galaxies, which allow us to dynamically calculate the physical properties associated with the baryons and the dark matter halo. For the former we assume a Freeman disc, while for the latter we employ the NFW and the Burkert halo profiles, separately. At the end, we compare the results of both cases with state-of-the-art cosmological galaxy simulations (EAGLE, TNG100 and TNG50). We find that the {\em cored} dark matter halo emerged as the dominant quantity from a radius 1-3 times the effective radius. Its fraction to the total mass is in good agreement with the outcome of hydrodynamical galaxy simulations. Remarkably, we found that the dark matter core of $z\sim 1$ star-forming galaxies are smaller and denser than their local counterparts. We conclude that dark matter halos have gradually expanded over the past 6.5 Gyrs. That is, observations are capable of capturing the dark matter response to the baryonic processes (e.g. feedbacks), and thus giving us the first empirical evidence of {\em gravitational potential fluctuations} in the inner region of galaxies, which can be verified with deep surveys and future missions.
Although CNNs have gained the ability to transfer learned knowledge from source task to target task by virtue of large annotated datasets but consume huge processing time to fine-tune without GPU. In this paper, we propose a new computationally efficient transfer learning approach using classification layer features of pre-trained CNNs by appending layer after existing classification layer. We demonstrate that fine-tuning of the appended layer with existing classification layer for new task converges much faster than baseline and in average outperforms baseline classification accuracy. Furthermore, we execute thorough experiments to examine the influence of quantity, similarity, and dissimilarity of training sets in our classification outcomes to demonstrate transferability of classification layer features.
Off-equilibrium dynamics of a three-dimensional lattice model with nearest- and next nearest-neighbors exclusions is studied. At equilibrium, the model undergoes a first-order fluid-solid transition. Non-equilibrium filling, through random sequential adsorption with diffusion, creates amorphous structures and terminates at a disordered state with random closest packing density that lies in the equilibrium solid regime. The approach towards random closest packing is characterized by two distinct power-law regimes, reflecting the formation of small densely packed grains in the long time regime of the filling process. We then study the fixed-density relaxation of these amorphous structures towards the solid phase. The route to crystallization is shown to deviate from the simple grain growth proposed by classical nucleation theory. Our measurements suggest that relaxation is driven mainly by coalescence of neighboring crystallized grains which exist in the initial amorphous state.
It is known that random convex polygonal lines on $\mathbb{Z}_+^2$ (with the endpoints fixed at $0=(0,0)$ and $n=(n_1,n_2)\to\infty$) have a limit shape with respect to the uniform probability measure, identified as the parabola arc $\sqrt{c\myp(1-x_1)}+\sqrt{x_2}=\sqrt{c}$, where $n_2/n_1\to c$. The present paper is concerned with the inverse problem of the limit shape. We show that for any strictly convex, $C^3$-smooth arc $\gamma\subset\mathbb{R}_+^2$ starting at the origin, there is a probability measure $P_n^\gamma$ on convex polygonal lines, under which the curve $\gamma$ is their limit shape.
We propose a mechanism for efficient heating of the solar chromosphere, based on non-ideal plasma effects. Three ingredients are needed for the work of this mechanism: (1) presence of neutral atoms; (2) presence of a non-potential magnetic field; (3) decrease of the collisional coupling of the plasma. Due to decrease of collisional coupling, a net relative motion appears between the neutral and ionized components, usually referred to as "ambipolar diffusion". This results in a significant enhancement of current dissipation as compared to the classical MHD case. We propose that the current dissipation in this situation is able to provide enough energy to heat the chromosphere by several kK on the time scale of minutes, or even seconds. In this paper, we show that this energy supply might be sufficient to balance the radiative energy losses of the chromosphere.
The paper presents a method by which the mean field dynamics of a population of dynamical systems with parameter diversity and global coupling can be described in terms of a few macroscopic degrees of freedom. The method applies to populations of any size and functional form in the region of coherence. It requires linear variation or a narrow distribution for the dispersed parameter. Although being an approximation, the method allows us to quantitatively study the collective regimes that arise as a result of diversity and coupling and to interpret the transitions among these regimes as bifurcations of the effective macroscopic degrees of freedom. To illustrate, the phenomenon of oscillator death and the route to full locking are examined for chaotic oscillators with time scale mismatch.
We study the 4-point function in the Keldysh formalism of the closed time path formulation of real time finite temperature field theory.   We derive the KMS conditions for these functions and discuss the number of 4-point functions that are independent. We define a set of `physical' functions which are linear combinations of the usual Keldysh functions. We show that these functions satisfy simple KMS conditions. In addition, we consider a set of integral equations which represent a resummation of ladder graphs. We show that these integral equations decouple when one uses the physical functions that we have defined. We discuss the generalization of these results to QED.
Nuclear matter and surface properties are carefully studied for a model based on an effective hadronic lagrangian with vector-vector and scalar-vector self-interactions. The results of the model are compared with those of the successful standard non-linear $\sigma-\omega$ model.
In this paper we present a minimality criterion for the Mumford-Shah functional, and more generally for non convex variational integrals on SBV which couple a surface and a bulk term. This method provides short and easy proofs for several minimality results.
We present a comprehensive and precise description of the Sagittarius (Sgr) stellar stream's 3D geometry as traced by its old stellar population. This analysis draws on the sample of ${\sim}44,000$ RR Lyrae (RRab) stars from the Pan-STARRS1 (PS1) 3$\pi$ survey (Hernitschek et al. 2016,Sesar et al. 2017b), which is ${\sim}80\%$ complete and ${\sim}90\%$ pure within 80~kpc, and extends to ${\gtrsim} 120$~kpc with a distance precision of ${\sim} 3\%$. A projection of RR Lyrae stars within $|\tilde{B}|_{\odot}<9^\circ$ of the Sgr stream's orbital plane reveals the morphology of both the leading and the trailing arms at very high contrast, across much of the sky. In particular, the map traces the stream near-contiguously through the distant apocenters. We fit a simple model for the mean distance and line-of-sight depth of the Sgr stream as a function of the orbital plane angle $\tilde{\Lambda}_{\odot}$, along with a power-law background-model for the field stars. This modeling results in estimates of the mean stream distance precise to ${\sim}1\%$ and it resolves the stream's line-of-sight depth. These improved geometric constraints can serve as new constraints for dynamical stream models.
This article is concerned with stochastic differential equations driven by a $d$ dimensional fractional Brownian motion with Hurst parameter $H>1/4$, understood in the rough paths sense. Whenever the coefficients of the equation satisfy a uniform ellipticity condition, we establish a sharp local estimate on the associated control distance function and a sharp local lower estimate on the density of the solution.
Gender is one of the most common attributes used to describe an individual. It is used in multiple domains such as human computer interaction, marketing, security, and demographic reports. Research has been performed to automate the task of gender recognition in constrained environment using face images, however, limited attention has been given to gender classification in unconstrained scenarios. This work attempts to address the challenging problem of gender classification in multi-spectral low resolution face images. We propose a robust Class Representative Autoencoder model, termed as AutoGen for the same. The proposed model aims to minimize the intra-class variations while maximizing the inter-class variations for the learned feature representations. Results on visible as well as near infrared spectrum data for different resolutions and multiple databases depict the efficacy of the proposed model. Comparative results with existing approaches and two commercial off-the-shelf systems further motivate the use of class representative features for classification.
Holoraumy is a tool being developed for dimensional enhancement (supersymmetry holography) where the goal is to build higher dimensional supersymmetric multiplets from lower dimensional supersymmetric multiplets. In this paper, for the first time we investigate holoraumy for on-shell supersymmetry. Specifically, the holoraumy tensors for a number of familiar 4D, $\mathcal{N}=1$ multiplets are calculated. It is shown in all of these cases of on-shell theories, the holoraumy is of the form of an electromagnetic duality charge multiplying a composite transformation involving an electromagnetic duality rotation through an angle of $\pi/2$ times a space time translation. The details of our calculations can be found at the HEPTHools Data Repository at https://hepthools.github.io/Data/.
We analyze an efficient frequency estimation scheme that is applied to measure the unknown frequency of an atomic state in Ramsey spectroscopy. The scheme is employing appropriate combinations of uncorrelated probe atoms and Greenburgur-Horne-Zeilinger (GHZ) type correlated probe atoms to estimate its frequency. The estimation value of frequency is obtained through the Bayesian analysis of the final measurement outcomes. The proposed scheme allows us to obtain better precision than the scheme without quantum correlation and it also prevents us from ambiguity in the frequency estimation procedure with GHZ correlations only. We show that the scheme can beat the shot-noise limit and, in addition, it is found that there is the trade-off relation between the precision of the frequency estimation and the decoherence rate in the atomic states.
We have imaged the emission from the near-infrared v=1-0 S(1), 1-0 S(7), 2-1 S(1) and 6-4 O(3) lines of molecular hydrogen in the N- and SW-Bars of M17, together with the hydrogen Br-gamma and Br-10 lines. This includes the first emission line image ever to be obtained of a line from the highly excited v=6 level of H2. In both Bars, the H2 emission is generally distributed in clumps along filamentary features. The 1-0 S(1) and 2-1 S(1) images have similar morphologies. Together with their relative line ratios, this supports a fluorescent origin for their emission, within a photodissociation region. The SW-Bar contains a clumpy medium, but in the N-Bar the density is roughly constant. The 1-0 S(7) line image is also similar to the 1-0 S(1) image, but the 6-4 O(3) image is significantly different to it. Since the emission wavelengths of these two lines are similar (1.748 to 1.733um), this cannot be due to differential extinction between the v=6 and the v=1 lines. We attribute the difference to the pumping of newly formed H2 into the v=6, or to a nearby, level. However, this also requires either a time-dependent photodissociation region (where molecule formation does not balance dissociation), rather than it to be in steady-state, and/or for the formation spectrum to vary with position in the source. If this interpretation of formation pumping of molecular hydrogen is correct, it is the first clear signature from this process to be seen.
This article briefly reviews three topics related to the quantum critical behavior of certain heavy-fermion systems. First, we summarize an extended dynamical mean-field theory for the Kondo lattice, which treats on an equal footing the quantum fluctuations associated with the Kondo and RKKY couplings. The dynamical mean-field equations describe an effective Kondo impurity model with an additional coupling to vector bosons. Two types of quantum phase transition appear to be possible within this approach---the first a conventional spin-density-wave transition, the second driven by local physics. For the second type of transition to be realized, the effective impurity model must have a quantum critical point exhibiting an anomalous local spin susceptibility. In the second part of the paper, such a critical point is shown to occur in two variants of the Kondo impurity problem. Finally, we propose an operational test for the existence of quantum critical behavior driven by local physics. Neutron scattering results suggest that CeCu$_{6-x}$Au$_x$ passes this test.
The magnetic stability of {\delta}-plutonium is analyzed taking into account zero-point spin fluctuations. Within the generalized theory of spin fluctuations described within a simple phenomenological model neglecting its spatial dispersion we show that zero-point local magnetic moments are giant (at.Pu) and suppress the magnetic order predicted by ab initio calculations resulting in the observed paramagnetic state of {\delta}-plutonium.
Many computer vision applications, such as object recognition and segmentation, increasingly build on superpixels. However, there have been so far few superpixel algorithms that systematically deal with noisy images. We propose to first decompose the image into equal-sized rectangular patches, which also sets the maximum superpixel size. Within each patch, a Potts model for simultaneous segmentation and denoising is applied, that guarantees connected and non-overlapping superpixels and also produces a denoised image. The corresponding optimization problem is formulated as a mixed integer linear program (MILP), and solved by a commercial solver. Extensive experiments on the BSDS500 dataset images with noises are compared with other state-of-the-art superpixel methods. Our method achieves the best result in terms of a combined score (OP) composed of the under-segmentation error, boundary recall and compactness.
We have carried out an initial study of a small sample of nearby spiral and barred galaxies with a broad distribution of Hubble types in order to have a first estimate of the magnitude of their secular mass accretion/excretion rates in the context of bulge building and morphological evolution along the Hubble sequence. The stellar surface density maps of the sample galaxies were derived from the archival data of SINGS and SDSS. The corresponding molecular and atomic surface densities were derived from archival CO(1-0) and HI interferometric observations of the BIMA SONG, THINGS, and VIVA surveys. The method used for determining the radial mass flow rates follows from our previous work using the potential-density phase shift approach, which utilizes a volume-type torque integral to calculate the angular momentum exchange rate between the basic state disk matter and the density wave modes. This approach yields radial mass flow rates and angular momentum transport rates several times higher than similar rates estimated using the traditional method of gravitational torque couple of Lynden-Bell and Kalnajs 1972, and this difference reflects the dominant role played by collisionless shocks in the secular evolution of galaxies containing extremely non-linear, quasi-steady density wave modes. It is shown that these non-linear modes maintains their quasi-steady state at the expense of a continuous radial mass flow and the resulting morphological transformation of galaxies throughout their lifetime, not only for late-type and intermediate-type disk galaxies but, under favorable conditions, also for earlier types including S0s and disky ellipticals. We show here for the first time using observational data that stellar mass accretion/excretion is just as important, and oftentimes much more important, than the corresponding accretion/excretion processes in the gaseous component.
We study half-BPS surface operators in N=2 supersymmetric QCD in four dimensions with gauge group SU(2) and four fundamental flavours. We compute the twisted chiral superpotential that describes the effective theory on the surface operator using equivariant localization as well as the Seiberg-Witten data. We then use the constraints imposed by S-duality to resum the instanton contributions to the twisted superpotential into elliptic functions and (quasi-) modular forms. The resummed results match what one would obtain from the description of surface operators as the insertion of a degenerate operator in a spherical conformal block in Liouville CFT.
The most effective use of data from current and upcoming large scale structure~(LSS) and CMB observations requires the ability to predict the clustering of LSS with very high precision. The Effective Field Theory of Large Scale Structure (EFTofLSS) provides an instrument for performing analytical computations of LSS observables with the required precision in the mildly nonlinear regime. In this paper, we develop efficient implementations of these computations that allow for an exploration of their dependence on cosmological parameters. They are based on two ideas. First, once an observable has been computed with high precision for a reference cosmology, for a new cosmology the same can be easily obtained with comparable precision just by adding the difference in that observable, evaluated with much less precision. Second, most cosmologies of interest are sufficiently close to the Planck best-fit cosmology that observables can be obtained from a Taylor expansion around the reference cosmology. These ideas are implemented for the matter power spectrum at two loops and are released as public codes. When applied to cosmologies that are within 3$\sigma$ of the Planck best-fit model, the first method evaluates the power spectrum in a few minutes on a laptop, with results that have 1\% or better precision, while with the Taylor expansion the same quantity is instantly generated with similar precision. The ideas and codes we present may easily be extended for other applications or higher-precision results.
We develop systematically to all orders the forward scattering description for retarded amplitudes in field theories at zero temperature. Subsequently, through the application of the thermal operator, we establish the forward scattering description at finite temperature. We argue that, beyond providing a graphical relation between the zero temperature and the finite temperature amplitudes, this method is calculationally quite useful. As an example, we derive the important features of the one loop retarded gluon self-energy in the hard thermal loop approximation from the corresponding properties of the zero temperature amplitude.
A simple graph $G=(V,E)$ is word-representable if there exists a word $w$ over the alphabet $V$ such that letters $x$ and $y$ alternate in $w$ iff $xy\in E$. Word-representable graphs generalize several important classes of graphs. A graph is word-representable iff it admits a semi-transitive orientation. We use semi-transitive orientations to enumerate connected non-word-representable graphs up to the size of 11 vertices, which led to a correction of a published result. Obtaining the enumeration results took 3 CPU years of computation.   Also, a graph is word-representable iff it is $k$-representable for some $k$, that is, if it can be represented using $k$ copies of each letter. The minimum such $k$ for a given graph is called graph's representation number. Our computational results in this paper not only include distribution of $k$-representable graphs on at most 9 vertices, but also have relevance to a known conjecture on these graphs. In particular, we find a new graph on 9 vertices with high representation number.   Finally, we introduce the notion of a $k$-semi-transitive orientation refining the notion of a semi-transitive orientation, and show computationally that the refinement is not equivalent to the original definition unlike the equivalence of $k$-representability and word-representability.
We have obtained IRTF/SpeX spectra of eight moderate-redshift (z=0.7-2.4), radio-selected (log R*~0.4-1.9) broad absorption line (BAL) quasars. The spectra cover the rest-frame optical band. We compare the optical properties of these quasars to those of canonically radio-quiet (log R*<1) BAL quasars at similar redshifts and to low-redshift quasars from the Palomar-Green catalog. As with previous studies of BAL quasars, we find that [OIII] 5007 is weak, and optical FeII emission is strong, a rare combination in canonically radio-loud (log R*>1) quasars. With our measurements of the optical properties, particularly the Balmer emission line widths and the continuum luminosity, we have used empirical scaling relations to estimate black hole masses and Eddington ratios. These lie in the range (0.4-2.6)x10^9 M_sun and 0.1-0.9, respectively. Despite their comparatively extreme radio properties relative to most BAL quasars, their optical properties are quite consistent with those of radio-quiet BAL quasars and dissimilar to those of radio-loud non-BAL quasars. While BAL quasars generally appear to have low values of [OIII]/FeII, an extreme of "Eigenvector 1", the Balmer line widths and Eddington ratios do not appear to significantly differ from those of unabsorbed quasars at similar redshifts and luminosities.
There is growing notion that black holes may not contain curvature singularities (and that indeed nature in general may abhor such spacetime defects). This notion could have implications on our understanding of the evolution of primordial black holes (PBHs) and possibly on their contribution to cosmic energy. This paper discusses the evolution of a non-singular black hole (NSBH) based on a recent model [1]. We begin with a study of the thermodynamic process of the black hole in this model, and demonstrate the existence of a maximum horizon temperature T_{max}, corresponding to a unique mass value. At this mass value the specific heat capacity C changes signs to positive and the body begins to lose its black hole characteristics. With no loss of generality, the model is used to discuss the time evolution of a primordial black hole (PBH), through the early radiation era of the universe to present, under the assumption that PBHs are non-singular. In particular, we track the evolution of two benchmark PBHs, namely the one radiating up to the end of the cosmic radiation domination era, and the one stopping to radiate currently, and in each case determine some useful features including the initial mass m_{f} and the corresponding time of formation t_{f}. It is found that along the evolutionary history of the universe the distribution of PBH remnant masses (PBH-RM) PBH-RMs follows a power law. We believe such a result can be a useful step in a study to establish current abundance of PBH-MRs.