ShantanuT01/DACTYL-Pretraining huggingface dataset:
Pattern formation induced by wrinkling is a very common phenomenon exhibited in soft-matter substrates. In all these systems wrinkles develop in presence of compressively stressed thin films lying on compliant substrates. Here we demonstrate the controlled growth of self-organized nanopatterns exploiting a wrinkling instability on a solid-state substrate. Soda-lime glasses are modified in the surface layers by a defocused ion beam which triggers the formation of a compressively stressed surface layer deprived of alkali ions. When the substrate is heated up near its glass transition temperature, the wrinkling instability boosts the growth rate of the pattern by about two orders of magnitude. High aspect ratio anisotropic ripples bound by faceted ridges are thus formed which represent an optimal template for guiding the growth of large area arrays of functional nanostructures. We demonstrate the engineering over large square cm areas of quasi-1D arrays of Au nanostripe dimers endowed with tunable plasmonic response, strong optical dichroism and high electrical conductivity. These peculiar functionalities allow to exploit these large area substrates as active metamaterials in nanophotonics, biosensing and optoelectronics.
In this paper, we revisit the proof of the large deviations principle of Wiener chaoses partially given by Borel, and then by Ledoux in its full form. We show that some heavy-tail phenomena observed in large deviations can be explained by the same mechanism as for the Wiener chaoses, meaning that the deviations are created, in a sense, by translations. More precisely, we prove a general large deviations principle for a certain class of functionals $f_n : \mathbb{R}^n \to \mathcal{X}$, where $\mathcal{X}$ is some metric space, under the $n$-fold probability measure $\nu_{\alpha}^n$, where $\nu_{\alpha} =Y_{\alpha}^{-1}e^{-|x|^{\alpha}}dx$, $\alpha \in (0,2]$, for which the large deviations are due to translations. We retrieve, as an application, the large deviations principles known for the Wigner matrices without Gaussian tails, of the empirical spectral measure by Bordenave and Caputo, the largest eigenvalue and traces of polynomials by the author. We also apply our large deviations result to the last-passage time, which yields a large deviations principle when the weights have the density $Z_{\alpha}^{-1} e^{-x^{\alpha}}$ with respect to Lebesgue measure on $\mathbb{R}_+$, with $\alpha \in (0,1)$.
We compute the Hodge numbers of the variation of Hodge structure of the middle cohomology (with compact support) of the Landau-Ginzburg model dual to a weighted projective space. We state a conjectural formula for the Hodge numbers of general hypergeometric variations.   We show that a general Landau-Ginzburg fibre is birational to a Calabi-Yau variety if and only if a general anticanonical section of the weighted projective space is Calabi-Yau. We analyse the 104 weighted 3-spaces with canonical singularities, and show that a general anticanonical section is not a K3 surface exactly in those 9 cases where a generic Landau-Ginzburg fibre is an elliptic surface of Kodaira dimension 1.
A numerical search for bosonic superconducting static vortex rings in a $U(1)_{A}\times U(1)_{W}$ model is presented. The fate of these rings without current, is to shrink due to their tension until extinction. The superconductivity of the loop does not seem to prevent shrinking. Current quenching takes place before stabilization.
In this paper we propose that bubbles of AdS within Minkowski spacetime, stabilized at a finite radius by stiff matter and an electromagnetic gas, can be an alternative endpoint of gravitational collapse. The bubbles are horizonless with a size up to 12.5% larger than their Schwarzschild radius depending on their charge. We argue that they are stable against small perturbations, and have thermodynamical properties similar to those of real black holes. We provide a realization of the bubbles within string theory that relies on a specific brane intersection giving rise to a shell carrying dissolved charges from lower dimensional D-branes as well as a gas of open strings. We also note that our construction provides a new way of understanding the entropy of Reissner-Nordstr\"om black holes in the extremal limit.
Detectingandsegmentingobjectswithinwholeslideimagesis essential in computational pathology workflow. Self-supervised learning (SSL) is appealing to such annotation-heavy tasks. Despite the extensive benchmarks in natural images for dense tasks, such studies are, unfortunately, absent in current works for pathology. Our paper intends to narrow this gap. We first benchmark representative SSL methods for dense prediction tasks in pathology images. Then, we propose concept contrastive learning (ConCL), an SSL framework for dense pre-training. We explore how ConCL performs with concepts provided by different sources and end up with proposing a simple dependency-free concept generating method that does not rely on external segmentation algorithms or saliency detection models. Extensive experiments demonstrate the superiority of ConCL over previous state-of-the-art SSL methods across different settings. Along our exploration, we distll several important and intriguing components contributing to the success of dense pre-training for pathology images. We hope this work could provide useful data points and encourage the community to conduct ConCL pre-training for problems of interest. Code is available.
We microscopically derive transport equations for the conduction electrons in ferromagnetic materials with an inhomogeneous magnetization profile. Our quantum kinetic approach includes elastic scattering and anisotropic spin-flip scattering at magnetic impurities. In the diffusive limit, we calculate the resistance through a domain wall and find that the domain-wall resistance can be positive or negative. In the limit of long domain walls we derive analytical expressions and compare them with existing works, which used less general models or different theoretical frameworks.
X-ray observations suggest high compactness of coronae in active galactic nuclei as well as in X-ray binaries. The compactness of the source implies a strong radial dependence in the illumination of the accretion disc. This will, for any reasonable radial profile of the density, lead to a radial profile of the disc ionisation. Svoboda et al. (2012) showed on a single example that assuming a radially-structured ionisation profile of the disc can cause an artificial increase of the radial-emissivity parameter. We further investigate how the X-ray spectra are modified and quantify this effect for a wide range of parameters. Computations are carried out with the current state-of-the-art models for relativistic reflection. We simulated spectra using the response files of the micro-calorimeter X-IFU, which is planned to be on board of Athena. We assumed typical parameters for X-ray bright Seyfert-1 galaxies and considered two scenarios for the disc ionisation: 1) a radial profile for the disc ionisation, 2) a constant disc ionisation. We found that steep emissivity profiles can be indeed achieved due to the radial profile of the disc ionisation, which becomes more important for the cases where the corona is located at low heights above the black hole and this effect may be even more prominent than the geometrical effects. We also found that the cases with high inner disc ionisation, rapidly decreasing with radius, may result in an inaccurate black hole spin measurements.
We present two-dimensional gaseous kinematics of the inner 1.2 $\times$ 1.8 kpc$^2$ of the Seyfert 2 galaxy NGC3081, from optical spectra (5600--7000\r{A}) obtained with the GMOS integral field spectrograph on the Gemini North telescope at a spatial resolution of $\approx$ 100pc. We have identified two-components in the line emitting gas. A narrower component (FWHM $\approx$ 60-100km s$^{-1}$), which appears to be gas in the galaxy disk, and which shows a distorted rotation pattern, is observed over the whole field of view. A broader component (FWHM $\approx$150-250 km s$^{-1}$) is present in the inner $\approx$ 2arcsec (200pc) and shows blueshifts and redshifts in the near and far sides of the galaxy, respectively, consistent with a bipolar outflow. Assuming this to be the case, we estimate that the mass outflow rate in ionized gas ($\dot{M}_{out}$) is between 1.9 $\times 10^{-3}$M$_{\odot}$ yr$^{-1}$ and 6.9 $\times 10^{-3}$M$_{\odot}$ yr$^{-1}$. The subtraction of a rotation model from the narrower component velocity field reveals a pattern of excess blueshifts of $\approx$ 50km s$^{-1}$ in the far side of the galaxy and similar excess redshifts in the near side, which are cospatial with a previously known nuclear bar. We interpret these residuals as due to gas following non-circular orbits in the barred potential. Under the assumption that these motions may lead to gas inflows, we estimate an upper limit for the mass inflow rate in ionized gas of $\phi$ $\approx$ 1.3 $\times 10^{-2}$M$_{\odot}$ yr$^{-1}$.
Representing visual signals by coordinate-based deep fully-connected networks has been shown advantageous in fitting complex details and solving inverse problems than discrete grid-based representation. However, acquiring such a continuous Implicit Neural Representation (INR) requires tedious per-scene training on tons of signal measurements, which limits its practicality. In this paper, we present a generic INR framework that achieves both data and training efficiency by learning a Neural Implicit Dictionary (NID) from a data collection and representing INR as a functional combination of basis sampled from the dictionary. Our NID assembles a group of coordinate-based subnetworks which are tuned to span the desired function space. After training, one can instantly and robustly acquire an unseen scene representation by solving the coding coefficients. To parallelly optimize a large group of networks, we borrow the idea from Mixture-of-Expert (MoE) to design and train our network with a sparse gating mechanism. Our experiments show that, NID can improve reconstruction of 2D images or 3D scenes by 2 orders of magnitude faster with up to 98% less input data. We further demonstrate various applications of NID in image inpainting and occlusion removal, which are considered to be challenging with vanilla INR. Our codes are available in https://github.com/VITA-Group/Neural-Implicit-Dict.
The bifurcated emission component (BEC) in the radio profile of the millisecond pulsar J1012+5307 can be interpreted as the signature of the curvature radiation beam polarised orthogonally to the plane of electron trajectory. Since the beam is intrinsically narrow (~1 deg), the associated emission region must be small for the observed BEC to avoid smearing out by spatial convolution. We estimate whether the energy available in the stream is sufficient to produce such a bright feature in the averaged profile. The energy considerations become complicated by the angular constraints imposed by the width of the microbeam, and by the specific spectrum of the BEC which is found to have the spectral index xi ~ -0.9 in comparison to the index of xi ~ -2 for the total profile. For typical parameters, the luminosity of the BEC is determined to be 4 10^{25} erg/s, whereas the maximum-possible beam-size-limited power of the stream is L_max ~ 2 10^{29} erg/s. This implies the minimum energy-conversion efficiency of eta ~ 2 10^{-4}. The BEC's luminosity does not exceed any absolute limits of energetics, in particular, it is smaller than the power of primary electron and/or secondary plasma stream. However, the implied efficiency of energy transfer into the radio band is extreme if the coherently emitting charge-separated plasma density is limited to the Goldreich-Julian value. This suggests that the bifurcated shape of the BEC has macroscopic origin, however, several uncertainties (eg. the dipole inclination and spectral shape) make this conclusion not firm.
Reliable measurements of the solar magnetic field are still restricted to the photosphere, and our present knowledge of the three-dimensional coronal magnetic field is largely based on extrapolation from photospheric magnetogram using physical models, e.g., the nonlinear force-free field (NLFFF) model as usually adopted. Most of the currently available NLFFF codes have been developed with computational volume like Cartesian box or spherical wedge while a global full-sphere extrapolation is still under developing. A high-performance global extrapolation code is in particular urgently needed considering that Solar Dynamics Observatory (SDO) can provide full-disk magnetogram with resolution up to $4096\times 4096$. In this work, we present a new parallelized code for global NLFFF extrapolation with the photosphere magnetogram as input. The method is based on magnetohydrodynamics relaxation approach, the CESE-MHD numerical scheme and a Yin-Yang spherical grid that is used to overcome the polar problems of the standard spherical grid. The code is validated by two full-sphere force-free solutions from Low & Lou's semi-analytic force-free field model. The code shows high accuracy and fast convergence, and can be ready for future practical application if combined with an adaptive mesh refinement technique.
Globular clusters are dense stellar systems whose core slowly contracts under the effect of self-gravity. The rate of this process was recently found to be directly linked to the initial amount of velocity anisotropy: tangentially anisotropic clusters contract faster than radially anisotropic ones. Furthermore, initially anisotropic clusters are found to generically tend towards more isotropic distributions during the onset of contraction. Chandrasekhar's "non-resonant" (NR) theory of diffusion describes this relaxation as being driven by a sequence of local two-body deflections along each star's orbit. We explicitly tailor this NR prediction to anisotropic clusters, and compare it with $N$-body realisations of Plummer spheres with varying degrees of anisotropy. The NR theory is shown to recover remarkably well the detailed shape of the orbital diffusion and the associated initial isotropisation, up to a global multiplicative prefactor which increases with anisotropy. Strikingly, a simple effective isotropic prescription provides almost as good a fit, as long as the cluster's anisotropy is not too strong. For these more extreme clusters, accounting for long-range resonant relaxation may be necessary to capture these clusters' long-term evolution.
In spacetime physics, we frequently need to consider a set of all spaces (`universes') as a whole. In particular, the concept of `closeness' between spaces is essential. However, there has been no established mathematical theory so far which deals with a space of spaces in a suitable manner for spacetime physics.   Based on the scheme of the spectral representation of geometry, we construct a space of all compact Riemannian manifolds equipped with the spectral measure of closeness. We show that this space of all spaces can be regarded as a metric space. We also show other desirable properties of this space, such as the partition of unity, locally-compactness and the second countability. These facts show that this space of all spaces can be a basic arena for spacetime physics.
The central object of this article is (a special version of) the Helfrich functional which is the sum of the Willmore functional and the area functional times a weight factor $\varepsilon\ge 0$. We collect several results concerning the existence of solutions to a Dirichlet boundary value problem for Helfrich surfaces of revolution and cover some specific regimes of boundary conditions and weight factors $\varepsilon\ge 0$. These results are obtained with the help of different techniques like an energy method, gluing techniques and the use of the implicit function theorem close to Helfrich cylinders. In particular, concerning the regime of boundary values, where a catenoid exists as a global minimiser of the area functional, existence of minimisers of the Helfrich functional is established for \emph{all} weight factors $\varepsilon\ge 0$. For the singular limit of weight factors $ \varepsilon \nearrow \infty $ they converge uniformly to the catenoid which minimises the surface area in the class of surfaces of revolution.
These results represent the solution for the historical problem of the contamination by matter effects on the CPV Asymmetry for neutrino oscillations. Vacuum is CPT-symmetric and matter is T-symmetric, the goal is accomplished by using this guiding principle. Independent of the theoretical framework for the dynamics of the active neutrino flavors, we prove the Disentanglement Theorem A(CP)=A(CP, T)+A(CP, CPT) for the experimental CPV Asymmetry, with A(CP, T) genuine T-odd and A(CP, CPT) fake CPT-odd. For the effective Hamiltonian written as the sum of free mass propagation plus the matter potential for electron-neutrinos, the two components have definite parities under the baseline L, the matter potential "a", the imaginary part $\sin\delta$ of the PMNS mixing matrix and the hierarchy "h"=$\pm 1$ in the neutrino mass ordering: A(CP, T) is odd in L and $\sin\delta$ plus even in a and h; A(CP, CPT) is even in L and $\sin\delta$ plus odd in a and almost odd in h. For present terrestrial accelerator sources of muon-neutrinos and antineutrinos, the two components of the appearance CPV asymmetry A(CP) can be disentangled by either baseline dependence (HKK) or energy dependence (DUNE). At the DUNE baseline, the higher energy region above the first oscillation node provides a dominant matter-induced A(CP, CPT) component and the sign of the experimental asymmetry A(CP) gives the hierarchy in the neutrino mass ordering. On the contrary, there is a "magic energy" E around the second oscillation maximum in which the fake A(CP, CPT) component has a first-rank zero whereas the genuine A(CP, T) component has a maximum proportional to sin{\delta}. With a modest energy resolution $\Delta E \sim 200$ MeV an effective zero remains in the matter-induced A(CP, CPT).
We used temperature dependent high-resolution x-ray powder diffraction and magnetization measurements to investigate structural, magnetic and electronic degrees of freedom across the ferromagnetic magneto-elastic phase transition in Mn1Fe1P0.6-wSi0.4Bw (w = 0, 0.02, 0.04, 0.06, 0.08). The magnetic transition was gradually tuned from a strong first-order (w = 0) towards a second-order magnetic transition by substituting P by B. Increasing the B content leads to a systematic increase in the magnetic transition temperature and a decrease in thermal hysteresis, which completely vanishes for w = 0.08. Furthermore, the largest changes in lattice parameter across the magnetic transition occur for w = 0, which systematically becomes smaller approaching the samples with w = 0.08. Electron density plots show a strong directional preference of the electronic distribution on the Fe site, which indicates the forming of bonds between Fe atoms and Fe and P/Si in the paramagnetic phase. On the other hand, the Mn-site shows no preferred directions resembling the behaviour of a free electron gas. Due to the low B concentrations (w = 0 - 0.08), distortions of the lattice are limited. However, even small amounts of B strongly disturb the overall topology of the electron density across the unit cell. Samples containing B show a strongly reduced variation in the electron density compared to the parent compound without B.
The advent of sensitive gravitational wave (GW) detectors, coupled with wide-field, high cadence optical time-domain surveys, raises the possibility of the first joint GW-electromagnetic (EM) detections of core-collapse supernovae (CCSNe). For targeted searches of GWs from CCSNe optical observations can be used to increase the sensitivity of the search by restricting the relevant time interval, defined here as the GW search window (GSW). The extent of the GSW is a critical factor in determining the achievable false alarm probability (FAP) for a triggered CCSN search. The ability to constrain the GSW from optical observations depends on how early a CCSN is detected, as well as the ability to model the early optical emission. Here we present several approaches to constrain the GSW, ranging in complexity from model-independent analytical fits of the early light curve, model-dependent fits of the rising or entire light curve, and a new data-driven approach using existing well-sampled CCSN light curves from {\it Kepler} and the Transiting Exoplanet Survey Satellite (TESS). We use these approaches to determine the time of core-collapse and its associated uncertainty (i.e., the GSW). We apply our methods to two Type II SNe that occurred during LIGO/Virgo Observing Run 3: SN\,2019fcn and SN\,2019ejj (both in the same galaxy at $d=15.7$ Mpc). Our approach shortens the duration of the GSW and improves the robustness of the GSW compared to techniques used in past GW CCSN searches.
The second and fourth Fourier harmonic of the azimuthal distribution of particles, $v_2$ and $v_4$, have been measured in Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC). The harmonic $v_4$ is mainly induced from $v_2$ as a higher-order effect. However, the ratio $v_4/(v_2)^2$ is significantly larger than predicted by hydrodynamics. Effects of partial thermalization are estimated on the basis of a transport calculation, and are shown to increase $v_4/(v_2)^2$ by a small amount. We argue that the large value of $v_4/(v_2)^2$ seen experimentally is mostly due to elliptic flow fluctations. However, the standard model of eccentricity fluctuations is unable to explain the large magnitude of $v_4/(v_2)^2$ in central collisions.
We study the localization transition in the integer quantum Hall effect as described by the network model of quantum percolation. Starting from a path integral representation of transport Green's functions for the network model, which employs both complex (bosonic) and Grassman (fermionic) fields, we map the problem of localization to the problem of diagonalizing a one-dimensional non-Hermitian Hamiltonian of interacting bosons and fermions. An exact solution is obtained in a restricted subspace of the Hilbert space which preserves boson-fermion supersymmetry. The physically relevant regime is investigated using the density matrix renormalization group (DMRG) method, and critical behavior is found at the plateau transition.
In The Delta Conjecture (arxiv:1509.07058), Haglund, Remmel and Wilson introduced a four variable $q,t,z,w$ Catalan polynomial, so named because the specialization of this polynomial at the values $(q,t,z,w) = (1,1,0,0)$ is equal to the Catalan number $\frac{1}{n+1}\binom{2n}{n}$. We prove the compositional version of this conjecture (which implies the non-compositional version) that states that the coefficient of $s_{r,1^{n-r}}$ in the expression $\Delta_{h_\ell} \nabla C_\alpha$ is equal to a weighted sum over decorated Dyck paths.
Recent ALMA observations have resolved the obscuring torus in the nearest Sy2 galaxy, NGC1068, in the millimeter band. These observations have confirmed the presence of a geometrically thick torus with an orbital motion of its matter and the velocity distribution which can reflect the clumpy structure. In the framework of N-body simulations we consider a dynamical model of an obscuring torus which accounts for the gravitational interaction between the clouds moving in the field of the central mass. In considered model, clouds are orbiting around the central mass exhibiting a spread in inclination and eccentricity. The self-gravity of the torus induces the velocity distribution of clouds with a global orbital motion which mimics the ALMA data for NGC1068.