ShantanuT01/DACTYL-Pretraining huggingface dataset:
We follow the time evolution of nonabelian gauge bosons from far-from-equilibrium initial conditions to thermal equilibrium by numerically solving an effective kinetic equation that becomes accurate in the weak coupling limit. We consider initial conditions that are either highly overoccupied or underoccupied. We find that overoccupied systems thermalize through a turbulent cascade reaching equilibrium in multiples of a thermalization time $t\approx 72./ (1-0.12\log \lambda)/\lambda^2 T$, whereas underoccupied systems undergo a "bottom-up" thermalization in a time $t\approx (34. +21. \ln(Q/T))/ (1-0.037\log \lambda)(Q/T)^{1/2}/\lambda^2 T$, where $Q$ is the characteristic momentum scale of the initial condition. We apply this result to model initial stages of heavy-ion collisions and find rapid thermalization roughly in a time $Qt \lesssim 10$ or $t\lesssim 1$ fm/c.
It is usually assumed that the ellipticity power spectrum measured in weak lensing observations can be expressed as an integral over the underlying matter power spectrum. This is true at second order in the gravitational potential. We extend the standard calculation, constructing all corrections to fourth order in the gravitational potential. There are four types of corrections: corrections to the lensing shear due to multiple-deflections; corrections due to the fact that shape distortions probe the reduced shear $\gamma/(1-\kappa)$ rather than the shear itself; corrections associated with the non-linear conversion of reduced shear to mean ellipticity; and corrections due to the fact that observational galaxy selection and shear measurement is based on galaxy brightnesses and sizes which have been (de)magnified by lensing. We show how the previously considered corrections to the shear power spectrum correspond to terms in our analysis, and highlight new terms that were not previously identified. All correction terms are given explicitly as integrals over the matter power spectrum, bispectrum, and trispectrum, and are numerically evaluated for the case of sources at z=1. We find agreement with previous works for the ${\mathcal O}(\Phi^3)$ terms. We find that for ambitious future surveys, the ${\mathcal O}(\Phi^4)$ terms affect the power spectrum at the ~ 1-5 $\sigma$ level; they will thus need to be accounted for, but are unlikely to represent a serious difficulty for weak lensing as a cosmological probe.
The integral observables for model-independent detections of Abelian Z' gauge boson in e^+ e^- -> mu^+ mu^- (tau^+ \tau^-) process with unpolarized beams at the ILC energies are proposed. They are based on the differential cross-section of deviations from the standard model predictions calculated with a low energy effective Lagrangian and taking into consideration the relations between the Z' couplings to the fermions derived already. Due to these relations, the cross-section exhibits angular distribution giving a possibility for introducing one- or two parameter observables which effectively fit the mass m_Z', the axial-vector (a_Z)'^2 and the product of vector couplings v_e v_mu (v_e v_tau). Comparison with other results and approaches is given.
We present the linear spin wave theory calculation of the superfluid phase of a hard-core boson $J$-$K$ model with nearest neighbour exchange $J$ and four-particle ring-exchange $K$ at half filling on the triangular lattice, as well as the phase diagrams of the system at zero and finite temperatures. We find that the pure $J$ model (XY model) which has a well known uniform superfluid phase with an ordered parameter $M_x=<S_i^x>\neq 0$ at zero temperature is quickly destroyed by the inclusion of a negative-$K$ ring-exchange interactions, favouring a state with a $(\frac{4\pi}{3}, 0)$ ordering wavevector. We further study the behaviour of the finite-temperature Kosterlitz-Thouless phase transition ($T_{KT}$) in the uniform superfluid phase, by forcing the universal quantum jump condition on the finite-temperature spin wave superfluid density. We find that for $K \textless 0$, the phase boundary monotonically decreases to T=0 at $K/J = -4/3$, where a phase transition is expected and $T_{KT}$ decreases rapidly while for positive $K$, $T_{KT}$ reaches a maximum at some $K\neq 0$. It has been shown on a square lattice using quantum Monte Carlo(QMC) simulations that for small $K\textgreater 0$ away from the XY point, the zero-temperature spin stiffness value of the XY model is decreased\cite{F}. Our result seems to agree with this trend found in QMC simulations.
This paper presents a comprehensive approach to the evaluation of macroscopic material parameters for natural stone and quarry masonry. To that end, a reliable non-linear material model on a meso-scale is developed to cover the random arrangement of stone blocks and quasi-brittle behaviour of both basic components, as well as the impaired cohesion and tensile strength on the interface between the blocks and mortar joints. The paper thus interrelates the following three problems: (i) definition of a suitable periodic unit cell (PUC) representing a particular masonry structure; (ii) derivation of material parameters of individual constituents either experimentally or running a mixed numerical-experimental problem; (iii) assessment of the macroscopic material parameters including the tensile and compressive strengths and fracture energy.
We apply symmetric tensor network state (TNS) to study the nearest neighbor spin-1/2 antiferromagnetic Heisenberg model on Kagome lattice. Our method keeps track of the global and gauge symmetries in TNS update procedure and in tensor renormalization group (TRG) calculation. We also introduce a very sensitive probe for the gap of the ground state -- the modular matrices, which can also determine the topological order if the ground state is gapped. We find that the ground state of Heisenberg model on Kagome lattice is a gapped spin liquid with the $\mathbb{Z}_2$-topological order (or toric code type), which has a long correlation length $\xi\sim 10$ unit cell length. We justify that the TRG method can handle very large systems with over thousands of spins. Such a long $\xi$ explains the gapless behaviors observed in simulations on smaller systems with less than 300 spins or shorter than 10 unit cell length. We also discuss experimental implications of the topological excitations encoded in our symmetric tensors.
By extending the response function approach developed in nonlinear optics, we analytically derive an expression for the non-Markovianity [Laine, et al, Phys. Rev. A 81, 062115 (2010)] in the time evolution of a system in contact with a quantum mechanical bath, and find a close connection with the directly observable nonlinear optical response. The result indicates that memory in the bath induced fluctuations rather than in the dissipation causes non-Markovianity. Initial correlations between states of the system and the bath are shown to be essential for a correct understanding of the non-Markovianity.
As helioseismology matures and turns into a precision science, modeling finite-frequency, geometric and systematical effects is becoming increasingly important. Here we introduce a general formulation for treating perturbations of arbitrary tensor rank in spherical geometry using fundamental ideas of quantum mechanics and their extensions in geophysics. We include line-of-sight projections and center-to-limb differences in line-formation heights in our analysis. We demonstrate the technique by computing a travel-time sensitivity kernel for sound-speed perturbations. The analysis produces the spherical harmonic coefficients of the sensitivity kernels, which leads to better-posed and computationally efficient inverse problems.
We define a multi-index filtration on the ring of germs of functions on a hypersurface singularity associated with its Newton diagram and compute the multivariable Poincar\'e series of this filtration in some cases.
The characterization of quantum correlations is crucial to the development of new quantum technologies and to understand how dramatically quantum theory departs from classical physics. Here we systematically study single- and multiparticle interference patterns produced by general two- and three-qubit systems. From this we establish on phenomenological grounds a new type of quantum correlation for these systems, which we name quantum interference, deriving some quantifiers that are given explicitly in terms of the density matrix elements of the complete system. By using these quantifiers, we show that, contrary to our expectations, entanglement is not a required property for a composite quantum system to manifest multiparticle interference.
This work describes a full Bayesian analysis of the Nearby Universe as traced by galaxies of the 2M++ survey. The analysis is run in two sequential steps. The first step self-consistently derives the luminosity dependent galaxy biases, the power-spectrum of matter fluctuations and matter density fields within a Gaussian statistic approximation. The second step makes a detailed analysis of the three dimensional Large Scale Structures, assuming a fixed bias model and a fixed cosmology. This second step allows for the reconstruction of both the final density field and the initial conditions at z=1000 assuming a fixed bias model. From these, we derive fields that self-consistently extrapolate the observed large scale structures. We give two examples of these extrapolation and their utility for the detection of structures: the visibility of the Sloan Great Wall, and the detection and characterization of the Local Void using DIVA, a Lagrangian based technique to classify structures.
The new project GENIUS will cover a wide range of the parameter space of predictions of SUSY for neutralinos as cold dark matter. Together with DAMA it will be the only experiment which can probe the seasonal modulation signal. Concerning hot dark matter GENIUS will be able to fix the (effective) neutrino mass with high accuracy. A GENIUS Test Facility has just been funded and will come into operation by end of 2002.
We consider the type I theory compactified on $T^3$. When the D5-brane wraps the $T^3$ it yields a D2-brane in seven dimensions. In the leading approximation the moduli space of vacua of the three dimensional field theory on the brane is $T^4/\ZZ_2$. The dual M theory description of this theory is a compactification on K3 and our 2-brane is the eleven dimensional 2-brane at a point in K3. We use this fact to conclude that strong coupling IR effects in the three dimensional theory on the brane turn its moduli space into a K3. This interpretation allows us to solve various strongly coupled gauge theories in three dimensions by identifying their Coulomb branch with a piece of a (sometime singular) K3.
Nonlinear quantum mechanics at the Planck scale can produce nonlocal effects contributing to resolution of singularities, to cosmic acceleration, and modified black-hole dynamics, while avoiding the usual causality issues.
We present CO(J= 1-0; 3-2; 5-4; 10-9) and 1.2-kpc resolution [CII] line observations of the dusty star-forming galaxy (SFG) HXMM05 -- carried out with the Karl G. Jansky Very Large Array, the Combined Array for Research in Millimeter-wave Astronomy, the Plateau de Bure Interferometer, and the Atacama Large Millimeter/submillimeter Array, measuring an unambiguous redshift of z = 2.9850+/-0.0009. We find that HXMM05 is a hyper-luminous infrared galaxy (LIR=(4+/-1)x10^13 Lsun) with a total molecular gas mass of (2.1+/-0.7)x10^11 (alpha_CO/0.8) Msun. The CO(J=1-0) and [CII] emission are extended over ~9 kpc in diameter, and the CO line FWHM exceeds 1100 km s^-1. The [CII] emission shows a monotonic velocity gradient consistent with a disk, with a maximum rotation velocity of v_c = 616+/-100 km s^-1 and a dynamical mass of (7.7+/-3.1)x10^11 Msun. We find a star formation rate (SFR) of 2900^750_-595 Msun yr^-1. HXMM05 is thus among the most intensely star-forming galaxies known at high redshift. Photo-dissociation region modeling suggests physical conditions similar to nearby SFGs, showing extended star formation, which is consistent with our finding that the gas and dust emission are co-spatial. Its molecular gas excitation resembles the local major merger Arp 220. The broad CO and [CII] lines and a pair of compact dust nuclei suggest the presence of a late-stage major merger at the center of the extended disk, again reminiscent of Arp 220. The observed gas kinematics and conditions together with the presence of a companion and the pair of nuclei suggest that HXMM05 is experiencing multiple mergers as a part of the evolution.
Density functional theory and density functional tight-binding are applied to model electron transport in copper nanowires of approximately 1 nm and 3 nm diameters with varying crystal orientation and surface termination. The copper nanowires studied are found to be metallic irrespective of diameter, crystal orientation and/or surface termination. Electron transmission is highly dependent on crystal orientation and surface termination. Nanowires oriented along the [110] crystallographic axis consistently exhibit the highest electron transmission while surface oxidized nanowires show significantly reduced electron transmission compared to unterminated nanowires. Transmission per unit area is calculated in each case, for a given crystal orientation we find that this value decreases with diameter for unterminated nanowires but is largely unaffected by diameter in surface oxidized nanowires for the size regime considered. Transmission pathway plots show that transmission is larger at the surface of unterminated nanowires than inside the nanowire and that transmission at the nanowire surface is significantly reduced by surface oxidation. Finally, we present a simple model which explains the transport per unit area dependence on diameter based on transmission pathways results.
For an asymptotically flat initial data, the Penrose inequality gives a lower bound of the Arnowitt-Deser-Misner total mass of a spacetime in terms of the area of certain surfaces representing black holes. This is a deep and beautiful refinement of the famous positive mass theorem and it plays an important role in the study of gravitational collapse. Gravitational collapse can also happen if sufficient mass is concentrated into a finite region. This motivates us to seek a localized version of the Penrose inequality. In this Letter, we successfully make a precise statement of this form for the Liu-Yau quasi-local mass in spherical symmetry.
We studied 16 sunspots with different sizes and shapes using the observations with the Hinode Solar Optical Telescope. The ratio of G-band and CaII H images reveal rich structures both within the umbra and penumbra of most spots. The striking features are the compact blob at the foot point of the umbra side of the penumbral fibrils with disk center-limb side asymmetry. In this paper, we present properties of these features using the spectropolarimetry and images in G-band, CaII and blue filters. We discuss the results using the contemporary models of the sunspots.
A $q$-discretization of \vi\ algebra is studied which reduces to the ordinary \vi\ algebra in the limit of $q \ra 1$. This is derived starting from the Moyal bracket algebra, hence is a kind of quantum deformation different from the quantum groups. Representation of this new algebra by using $q$-parametrized free fields is also given.
In many advanced video based applications background modeling is a pre-processing step to eliminate redundant data, for instance in tracking or video surveillance applications. Over the past years background subtraction is usually based on low level or hand-crafted features such as raw color components, gradients, or local binary patterns. The background subtraction algorithms performance suffer in the presence of various challenges such as dynamic backgrounds, photometric variations, camera jitters, and shadows. To handle these challenges for the purpose of accurate background modeling we propose a unified framework based on the algorithm of image inpainting. It is an unsupervised visual feature learning hybrid Generative Adversarial algorithm based on context prediction. We have also presented the solution of random region inpainting by the fusion of center region inpaiting and random region inpainting with the help of poisson blending technique. Furthermore we also evaluated foreground object detection with the fusion of our proposed method and morphological operations. The comparison of our proposed method with 12 state-of-the-art methods shows its stability in the application of background estimation and foreground detection.
We report on our discovery and follow-up observations of the X-ray source SAX J1747.0-2853 detected in outburst on 1998, March 10 with the BeppoSAX Wide Field Cameras in the energy range 2-28 keV. The source is located about half degree off the Galactic Nucleus. A total of 14 type-I X-ray bursts were detected in Spring 1998, thus identifying the object as a likely low-mass X-ray binary harboring a weakly magnetized neutron star. Evidence for photospheric radius expansion is present in at least one of the observed bursts, leading to an estimate of the source distance of about 9 kpc. We performed a follow-up target of opportunity observation with the BeppoSAX Narrow Field Instruments on March 23 for a total elapsed time of 72 ks. The source persistent luminosity was 2.6x10^36 erg/s in the 2-10 keV energy range. The wide band spectral data (1-200 keV) are consistent with a remarkable hard X-ray spectrum detected up to 150 keV, highly absorbed at low energies (Nh of the order of 10^23 cm^-2) and with clear evidence for an absorption edge near 7 keV. A soft thermal component is also observed, which can be described by single temperature blackbody emission at about 0.6 keV.
We develop the notion of double holography in Type IIB string theory realizations of braneworld models. The Type IIB setups are based on the holographic duals of 4d BCFTs comprising 4d $\mathcal N=4$ SYM on a half space coupled to 3d $\mathcal N=4$ SCFTs on the boundary. Based on the concrete BCFTs and their brane construction, we provide microscopic realizations of the intermediate holographic description, obtained by dualizing only the 3d degrees of freedom. Triggered by recent observations in bottom-up models, we discuss the causal structures in the full BCFT duals and intermediate descriptions. This confirms qualitative features found in the bottom-up models but suggests a refinement of their interpretation.
Existing fast algorithms for bilateral and nonlocal means filtering mostly work with grayscale images. They cannot easily be extended to high-dimensional data such as color and hyperspectral images, patch-based data, flow-fields, etc. In this paper, we propose a fast algorithm for high-dimensional bilateral and nonlocal means filtering. Unlike existing approaches, where the focus is on approximating the data (using quantization) or the filter kernel (via analytic expansions), we locally approximate the kernel using weighted and shifted copies of a Gaussian, where the weights and shifts are inferred from the data. The algorithm emerging from the proposed approximation essentially involves clustering and fast convolutions, and is easy to implement. Moreover, a variant of our algorithm comes with a guarantee (bound) on the approximation error, which is not enjoyed by existing algorithms. We present some results for high-dimensional bilateral and nonlocal means filtering to demonstrate the speed and accuracy of our proposal. Moreover, we also show that our algorithm can outperform state-of-the-art fast approximations in terms of accuracy and timing.
The efficient integration of transition metal dichalcogenides (TMDs) into the current electronic device technology requires mastering the techniques of effective tuning of their optoelectronic properties. Specifically, controllable doping is essential. For conventional bulk semiconductors, ion implantation is the most developed method offering stable and tunable doping. In this work, we demonstrate n-type doping in MoSe2 flakes realized by low-energy ion implantation of Cl+ ions followed by millisecond-range flash lamp annealing (FLA). We further show that FLA for 3 ms with a peak temperature of about 1000 {\deg}C is enough to recrystallize implanted MoSe2. The Cl distribution in few-layer-thick MoSe2 is measured by secondary ion mass spectrometry. An increase in the electron concentration with increasing Cl fluence is determined from the softening and red shift of the Raman-active A_1g phonon mode due to the Fano effect. The electrical measurements confirm the n-type doping of Cl-implanted MoSe2. A comparison of the results of our density functional theory calculations and experimental temperature-dependent micro-Raman spectroscopy data indicates that Cl atoms are incorporated into the atomic network of MoSe2 as substitutional donor impurities.
Previous works suggested that the state transitions in an X-ray binary can be triggered by accreting inverse magnetic field from its companion star. A key point of this mechanism is the accretion and magnification of large-scale magnetic fields from outer boundary of a thin disk. However, how such a process can be realized is still an open question. In this work, we check this issue in a realistic X-ray binary system. According to our calculations, a quite strong initial magnetic field $B\sim 10^2-10^3$ G is required in order to assure that the large-scale magnetic field can be effectively dragged inward and magnified with the accretion of gas. Thus, such a picture probably can be present in high-mass X-ray binaries possessing strong stellar magnetic field, e.g., Cyg X-1.
The disk-outflow connection is thought to play a key role in extracting excess angular momentum from a forming protostar. We present ALMA 0.25" angular resolution observations - in the dust continuum at 1.33 mm and of the molecular line transitions of $^{12}$CO(2-1) and $^{13}$CO(2-1) - of the circumstellar disk and outflow around the T Tauri star HH30, a rare and beautiful example of a pre-main sequence star exhibiting a flared edge-on disk, an optical jet, and a CO molecular outflow.   The 1.3 mm continuum emission shows a remarkable elongated morphology along PA=31.2{\deg}+/-0.1{\deg} that has a constant brightness out to a radius of r=75 au. The emission is marginally resolved in the transverse direction, implying an intrinsic vertical width $\leq$24 au and an inclination to the line-of-sight i$\geq$84.8{\deg}. The monopolar outflow, detected in $^{12}$CO, arises from the north-eastern face of the disk from a disk radius r$\leq$22 au and extends up to 5" (or 700 au) above the disk plane.   We derive a lower limit to the total mass of the CO cavity/outflow of 1.7E-5 M$_\odot$. The CO cavity morphology is that of a hollow cone with semi-opening angle ~35{\deg}. The derived kinematics are consistent with gas flowing along the conical surface with a constant velocity of 9.3+/-0.7 km/s. We detect small rotation signatures (Vphi x sin(i) $\in$ [0.1;0.5] km/s) in the same sense as the underlying circumstellar disk. From these rotation signatures we infer an average specific angular momentum of the outflow of 38+/-15 au km/s at altitudes z<250 au. We also report the detection of small amplitude wiggling (1.2{\deg}) of the CO axis around an average inclination to the line of sight of i=91{\deg}.   The derived morphology and kinematics of the CO cavity are compatible with expectations from a slow disk wind, originating either through photo-evaporation or magneto-centrifugal processes.