ShantanuT01/DACTYL-Pretraining huggingface dataset:
As a variant of standard convolution, a dilated convolution can control effective receptive fields and handle large scale variance of objects without introducing additional computational costs. To fully explore the potential of dilated convolution, we proposed a new type of dilated convolution (referred to as inception convolution), where the convolution operations have independent dilation patterns among different axes, channels and layers. To develop a practical method for learning complex inception convolution based on the data, a simple but effective search algorithm, referred to as efficient dilation optimization (EDO), is developed. Based on statistical optimization, the EDO method operates in a low-cost manner and is extremely fast when it is applied on large scale datasets. Empirical results validate that our method achieves consistent performance gains for image recognition, object detection, instance segmentation, human detection, and human pose estimation. For instance, by simply replacing the 3x3 standard convolution in the ResNet-50 backbone with inception convolution, we significantly improve the AP of Faster R-CNN from 36.4% to 39.2% on MS COCO.
A real algebraic variety W of dimension m is said to be uniformly rational if each of its points has a Zariski open neighborhood which is biregularly isomorphic to a Zariski open subset of R^m. Let l be any nonnegative integer. We prove that every map of class C^l from a compact subset of a real algebraic variety into a uniformly rational real algebraic variety can be approximated in the C^l topology by piecewise-regular maps of class C^k, where k is an arbitrary integer greater than or equal to l. Next we derive consequences regarding algebraization of topological vector bundles.
We present the first results from RomulusC, the highest resolution cosmological hydrodynamic simulation of a galaxy cluster run to date. RomulusC, a zoom-in simulation of a halo with $z=0$ mass $10^{14}$ M$_{\odot}$, is run with the same sub-grid physics and resolution as Romulus25 (Tremmel et al. 2017). With unprecedented mass and spatial resolution, RomulusC represents a unique opportunity to study the evolution of galaxies in dense environments down to dwarf masses. We demonstrate that RomulusC results in an intracluster medium (ICM) consistent with observations. The star formation history and stellar mass of the brightest cluster galaxy (BCG) is consistent with observations and abundance matching results, indicating that our sub-grid models, optimized only to reproduce observations of field dwarf and Milky Way mass galaxies, are able to produce reasonable galaxy masses and star formation histories in much higher mass systems. Feedback from supermassive black holes (SMBHs) regulates star formation by driving large-scale, collimated outflows that coexist with a low entropy core. We find that non-BCG cluster member galaxies are substantially quenched compared to the field down to dwarf galaxy masses and, at low masses, quenching is seen to have no dependence on mass or distance from the cluster center. This enhanced quenched population extends beyond $R_{200}$ and is in place at high redshift. Similarly, we predict that SMBH activity is significantly suppressed within clusters outside of the BCG, but show how the effect could be lost when only focusing on the brightest AGN in the most massive galaxies.
We present a theoretical framework that accounts for the new $D_J$ and $D_{sJ}$ mesons measured in the open-charm sector. These resonances are properly described if considered as a mixture of conventional $P-$wave quark-antiquark states and four-quark components. The narrowest states are basically $P-$wave quark-antiquark mesons, while the dominantly four-quark states are shifted above the corresponding two-meson threshold. We study the electromagnetic decay widths as basic tools to scrutiny their nature.
We examine the prospects for studying the pre-reionization intergalactic medium (IGM) through the so-called 21 cm forest in spectra of bright high-redshift radio sources. We first compute the evolution of the mean optical depth for models that include X-ray heating of the IGM gas, Wouthuysen-Field coupling, and reionization. Under most circumstances, the spin temperature T_S grows large well before reionization begins in earnest. As a result, the optical depth is less than 0.001 throughout most of reionization, and background sources must sit well beyond the reionization surface in order to experience measurable absorption. HII regions produce relatively large "transmission gaps" and may therefore still be observable during the early stages of reionization. Absorption from sheets and filaments in the cosmic web fades once T_S becomes large and should be rare during reionization. Minihalos can produce strong (albeit narrow) absorption features. Measuring their abundance would yield useful limits on the strength of feedback processes in the IGM as well as their effect on reionization.
For a group $G,$ the enhanced power graph of $G$ is a graph with vertex set $G$ in which two distinct elements $x, y$ are adjacent if and only if there exists an element $w$ in $G$ such that both $x$ and $y$ are powers of $w.$ The proper enhanced power graph is the induced subgraph of the enhanced power graph on the set $G \setminus S,$ where $S$ is the set of dominating vertices of the enhanced power graph. In this paper, we first characterize the dominating vertices of enhanced power graph of any finite nilpotent group. Thereafter, we classify all nilpotent groups $G$ such that the proper enhanced power graphs are connected and find out their diameter. We also explicitly find out the domination number of proper enhanced power graphs of finite nilpotent groups. Finally, we determine the multiplicity of the Laplacian spectral radius of the enhanced power graphs of nilpotent groups.
The large two-pion exchange amplitudes are calculated in HB$\chi$PT and their net contribution to the reaction cross section is large.
In this work we investigate doping and temperature dependences of electronic structure of system with strong electronic correlations and strong electron-phonon interaction modeling cuprates in the frameworks of the three-band p-d-Holstein model by a polaronic version of the generalized tight binding (GTB) method. Within this approach the electronic structure is formed by polaronic quasiparticles constructed as excitations between initial and final polaronic multielectron states. Doping and temperature effects are taken into account by occupation numbers of local excited polaronic states and variations in the magnitude of spin-spin correlation functions. Both effects are manifested in the reconstruction of band structure, Fermi contours, density of states and redistribution of the spectral weight over the Hubbard polaron subbands. Doping leads to transformation of Fermi contour from small hole pockets around k=(pi/2,pi/2) with inhomogeneous spectral weight distribution at small hole concentration to large contour around k=(pi,pi) in the overdoped compound as a result of two quantum phase transitions. In the system with phonon subsystem and EPI doping results in the top of the valence band splitting off and new polaron subbands appearance. Temperature increasing in the system with doped holes and moderate EPI leads to formation of the flatband around k=(pi,pi) and transfer of the spectral weight to the splitted off top of the valence band.
Negative differential thermal resistance (NDTR) in approximate graphene nanoribbons (GNRs) is investigated from one dimension to three dimensions by using classical molecular dynamics method. For single-layer GNRs, NDTR can not be observed for very narrow GNRs (one dimension), NDTR appears when the width of GNRs increases (two dimensions). However, NDTR disappears gradually on further increasing the width. For multiple-layer GNRs, when the number of the layers increases, GNRs becomes from two-dimensional system to three-dimensional system, NDTR regime reduces and eventually disappears. In addition, when the length of GNRs increases, NDTR regime also reduces and vanishes in the thermodynamic limit. These effects may be useful for designing thermal devices where NDTR plays an important role.
To confront the transplanckian problem encountered in the backward extrapolation of the cosmological expansion of the momenta of the modes of quantum field theory, it is proposed that there is a reservoir, depository of transplanckian degrees of freedom. These are solicited by the cisplanckian modes so as to keep their density fixed and the total energy density of vacuum at a minimum.   The mechanism is due to mode - reservoir interaction, whereupon virtual quantum processes give rise to an effective mode-mode attraction. A BCS condensate results. It has a massless and massy collective excitation, the latter identified with the inflaton. For an effective non dimensional mode-reservoir coupling constant, g approx 0.3, the order of magnitude of its mass is what is required to account for cosmological fluctuations i.e. O(10^-6 -> 10^-5)m_Planck.
Flux-averaged and flux-integrated cross sections for quasi-elastic neutrino charged-current scattering on nucleus are analyzed. It is shown that the flux-integrated differential cross sections are nuclear model-independent. We calculate these cross sections using the relativistic distorted-wave impulse approximation and relativistic Fermi gas model with the Booster Neutrino Beamline flux and compare results with the recent MiniBooNE experiment data. Within these models an axial mass $M_A$ is extracted from a fit of the measured $d\sigma/dQ^2$ cross section. The extracted value of $M_A$ is consistent with the MiniBooNE result. The measured and calculated double differential cross sections $d\sigma/dTd\cos\theta$ generally agree within the error of the experiment. But the Fermi gas model predictions are completely off of the data in the region of low muon energies and scattering angles.
We show that a 2-leg ladder hamiltonian introduced recently by Albeverio and Fei (cond-mat/9807341) can be made to satisfy the Hecke algebra. As a result we have found an equivalent representation of the eigenspectrum in terms of the spin-1/2 antiferromagnetic XXZ chain at $\Delta = - 5/3$. The values of thermodynamic quantities such as the ground state energy and mass gap follow from the known XXZ results.
If A is an abelian variety over a number field K, and L is a (possibly infinite) extension of K generated by torsion points of A, then the quotient of A(L) by its torsion subgroup is a free abelian group.
We present a method to derive the logarithmic extinction coefficient in optical wavelengths using the emission lines of HeI. Using this procedure we can avoid selection biases when studying regions with different surface brightness and we can obtain better measurements of temperature lines, for example [SIII]6312.
The non-perturbative low energy effective action of N=2 SYM is studied within a microscopic string realization via D3/D-instanton systems. The localization deformation of instanton moduli space which has allowed the exact computation of multi-instanton contributions is, in this setting, due to a RR graviphoton background. The relation of deformed instanton contributions to topological string amplitudes on CY, argued by Nekrasov, appears quite natural in this framework. Based on arXiv:hep-th/0606013.
In this short note, we show that multi-partite $W$-type state is up to local unitaries uniquely determined by its reduced density matrices.
For positive integers k,n, we investigate the simplicial complex NM_k(n) of all graphs G on vertex set [n] such that every matching in G has size less than k. This complex (along with other associated cell complexes) is found to be homotopy equivalent to a wedge of spheres. The number and dimension of the spheres in the wedge are determined, and (partially conjectural) links to other combinatorially defined complexes are described. In addition we study for positive integers r,s and k the simplicial complex BNM_k(n) of all bipartite graphs G on bipartition [r] \cup [\bar{s}] such that there is no matching of size k in G, and obtain results similar to those obtained for NM_k(n).
We describe application of the `shapelet' linear decomposition of galaxy images to morphological classification using images of $\sim$ 3000 galaxies from the Sloan Digital Sky Survey. After decomposing the galaxies we perform a principal component analysis to reduce the number of dimensions of the shapelet space to nine. We find that each of these nine principal components contains unique morphological information, and give a description of each principal component's contribution to a galaxy's morphology. We find that galaxies of differing Hubble type separate cleanly in the shapelet space. We apply a Gaussian mixture model to the 9-dimensional space spanned by the principal components and use the results as a basis for classification. Using the mixture model, we separate galaxies into seven classes and give a description of each class's physical and morphological properties. We find that several of the mixture model classes correlate well with the traditional Hubble types both in their morphology and their physical parameters (e.g., color, velocity dispersions, etc.). In addition, we find an additional class of late-type morphology but with high velocity dispersions and very blue color; most of these galaxies exhibit post-starburst activity. This method provides an objective and quantitative alternative to traditional and subjective visual classification.
Video frame synthesis, which consists of interpolation and extrapolation, is an essential video processing technique that can be applied to various scenarios. However, most existing methods cannot handle small objects or large motion well, especially in high-resolution videos such as 4K videos. To eliminate such limitations, we introduce a neighbor correspondence matching (NCM) algorithm for flow-based frame synthesis. Since the current frame is not available in video frame synthesis, NCM is performed in a current-frame-agnostic fashion to establish multi-scale correspondences in the spatial-temporal neighborhoods of each pixel. Based on the powerful motion representation capability of NCM, we further propose to estimate intermediate flows for frame synthesis in a heterogeneous coarse-to-fine scheme. Specifically, the coarse-scale module is designed to leverage neighbor correspondences to capture large motion, while the fine-scale module is more computationally efficient to speed up the estimation process. Both modules are trained progressively to eliminate the resolution gap between training dataset and real-world videos. Experimental results show that NCM achieves state-of-the-art performance on several benchmarks. In addition, NCM can be applied to various practical scenarios such as video compression to achieve better performance.
In this article, we study the quantum transport through a single-level quantum-dot in Kondo regime, coupled to current leads and embedded between two one-dimensional topological superconductors, each hosting Majorana zero modes at their ends. The Kondo effect in the quantum dot is modeled by mean-field finite-$U$ auxiliary bosons approximation and solved by using the non-equilibrium Green's function approach. First, we calculate the density of states of the quantum dot, and then both the current and the differential conductance through the quantum dot in order to characterize the interplay between the Kondo resonance and Majorana zero modes. The results reveal that the presence of Majorana zero modes modifies the Kondo resonance exhibiting an anti-resonance structure in the density of states, leading to obtain spin-resolved behavior of the measurable current and differential conductance. We believe our findings could be helpful to understand the behavior of the Kondo effect in connection with Majorana zero modes.
Extracting class activation maps (CAM) is a key step for weakly-supervised semantic segmentation (WSSS). The CAM of convolution neural networks fails to capture long-range feature dependency on the image and result in the coverage on only foreground object parts, i.e., a lot of false negatives. An intuitive solution is ``coupling'' the CAM with the long-range attention matrix of visual transformers (ViT) We find that the direct ``coupling'', e.g., pixel-wise multiplication of attention and activation, achieves a more global coverage (on the foreground), but unfortunately goes with a great increase of false positives, i.e., background pixels are mistakenly included. This paper aims to tackle this issue. It proposes a new method to couple CAM and Attention matrix in a probabilistic Diffusion way, and dub it AD-CAM. Intuitively, it integrates ViT attention and CAM activation in a conservative and convincing way. Conservative is achieved by refining the attention between a pair of pixels based on their respective attentions to common neighbors, where the intuition is two pixels having very different neighborhoods are rarely dependent, i.e., their attention should be reduced. Convincing is achieved by diffusing a pixel's activation to its neighbors (on the CAM) in proportion to the corresponding attentions (on the AM). In experiments, our results on two challenging WSSS benchmarks PASCAL VOC and MS~COCO show that AD-CAM as pseudo labels can yield stronger WSSS models than the state-of-the-art variants of CAM.
Using Herschel PACS and SPIRE observations as part of the HerMES, we explore the far-IR properties of a sample of mid-IR selected starburst dominated ultra-luminous infrared galaxies (ULIRGs) at z ~ 2. We derive robust estimates of infrared luminosities (L_IR) and dust temperatures (Td) of the population and find that galaxies in our sample range from those that are as cold as high-z sub-millimeter galaxies (SMGs) to those that are as warm as optically faint radio galaxies (OFRGs) and local ULIRGs. We also demonstrate that a significant fraction of our sample would be missed from ground based (sub)mm surveys (850-1200{\mu}m) showing that the latter introduce a bias towards the detection of colder sources. Similarly, based on PACS data as part of the PEP project, we construct for the first time the full average SED of a sub-sample of infrared luminous Lyman break galaxies at z ~ 3, and find them to have higher T_d when compared to that of SMGs with comparable L_IR. We conclude that high-z ULIRGs span a wide range of dust temperatures, larger than that seen in local ULIRGs, and that Herschel data provide the means to characterize the bulk of the ULIRG population, free from selection biases introduced by ground based (sub)mm surveys.
Let $X$ be an algebraic variety, $f$ a regular function, $j:U\subset X$ the complement to the locus of vanishing of $f$, and $M$ a holonomic D-module on $U$.   Consider the $D_U[s]$-module $M\otimes "f^s"$. The goal of this note is to describe all $D_X[s]$-submodules $N\subset j_*(M\otimes "f^s")$ such that $j^*(N)\simeq M\otimes "f^s"$.
We study the unconventional insulating state in A_4C_{60} with a variety of approaches, including density functional calculations and dynamical mean-field theory. While the former predicts a metallic state, in disagreement with experiment, the latter yields a (paramagnetic) Mott-Jahn-Teller insulator. In that state, conduction between molecules is blocked by on-site Coulomb repulsion, magnetism is suppressed by intra-molecular Jahn-Teller effect, and important excitations (such as optical and spin gap) should be essentially intra-molecular. Experimental gaps of 0.5 eV and 0.1 eV respectively compare well with molecular ion values, in agreement with this picture.
We recover a nonlinear magnetic Schr\"odinger potential from measurement on an arbitrarily small open subset of the boundary on a compact Riemann surface. We assume that the magnetic potential satisfies suitable analytic properties, in which case the recovery can be obtained by a linearisation argument. The proof relies on the complex analytic methods introduced in [15].
Fano effect arising from interference between two dissipation channels to the radiation continuum enables to tune the photon statistics. Understanding the role of Fano effect and exploiting to achieve strong photon correlations are of both fundamental and applied significance. We present an analytical description of Fano-enhanced photon correlations based on cavity quantum electrodynamics to show that, the Fano effect in atom-cavity systems can improve the degree of antibunching by over four orders of magnitude. The enhancement factors and the optimal conditions are explicitly given, and found related to the Fano parameter $q$. Remarkably, the Fano enhancement manifests robustness against the decoherence processes, and can survive in the weak coupling regime. We expect our work to provide insight in tuning the photon statistics through Fano effect, which offers a new route to enhance the photon correlations, as well as the possibility of generating nonclassical light in a wider diversity of systems without the need of strong light-matter interaction.
We show that a function $\tan(1/it)$ is a Pick function (free-infinitely divisible transform) and indicate its connections with a probability. Moreover, we found its "counterpart" in classical infinitely divisible measures expressed as series of Rademacher variables.
Let $E/\mathbb{Q}$ be an elliptic curve which has split multiplicative reduction at a prime $p$ and whose analytic rank $r_{an}(E)$ equals one. The main goal of this article is to relate the second order derivative of the Mazur-Tate-Teitelbaum $p$-adic $L$-function $L_p(E,s)$ of $E$ to Nekov\'{a}\v{r}'s height pairing evaluated on natural elements arising from the Beilinson-Kato elements. Along the way, we extend a Rubin-style formula of Nekov\'a\v{r} (or in an alternative wording, correct another Rubin-style formula of his) to apply in the presence of exceptional zeros. Our height formula allows us, among other things, to compare the order of vanishing of $L_p(E,s)$ at $s=1$ to its (complex) analytic rank $r_{an}(E)$ assuming the non-triviality of the height pairing. This has consequences towards a conjecture of Mazur, Tate and Teitelbaum.
We have carried out a set of Monte Carlo simulations to study a number of fundamental aspects of the dynamical evolution of multiple stellar populations in globular clusters with different initial masses, fractions of second generation (2G) stars, and structural properties. Our simulations explore and elucidate: 1) the role of early and long-term dynamical processes and stellar escape in the evolution of the fraction of 2G stars and the link between the evolution of the fraction of 2G stars and various dynamical parameters; 2) the link between the fraction of 2G stars inside the cluster and in the population of escaping stars during a cluster's dynamical evolution; 3) the dynamics of the spatial mixing of the first-generation (1G) and 2G stars and the details of the structural properties of the two populations as they evolve toward mixing; 4) the implications of the initial differences between the spatial distribution of 1G and 2G stars for the evolution of the anisotropy in the velocity distribution and the expected radial profile of the 1G and 2G anisotropy for clusters at different stages of their dynamical history; 5) the variation of the degree of energy equipartition of the 1G and the 2G populations as a function of the distance from the cluster's centre and the cluster's evolutionary phase.