ShantanuT01/DACTYL-Pretraining huggingface dataset:
We present millimeter interferometric observations of the young stellar object SVS13 in NCG1333 in the N2H+(1-0) line and at 1.4 and 3mm dust continuum, using the IRAM Plateau de Bure interferometer. The results are complemented by infrared data from the Spitzer Space Telescope. The millimeter dust continuum images resolve four sources (A, B, C, and VLA3) in SVS13. With the dust continuum images, we derive gas masses of 0.2-1.1 M_sun for the sources. N2H+(1-0) line emission is detected and spatially associated with the dust continuum sources B and VLA3. The observed mean line width is ~0.48 km/s and the estimated virial mass is ~0.7 M_sun. By simultaneously fitting the seven hyperfine line components of N2H+, we derive the velocity field and find a symmetric velocity gradient of about 28 km/s/pc across sources B and VLA3, which could be explained by core rotation. The velocity field suggests that sources B and VLA3 are forming a physically bound protobinary system embedded in a common N2H+ core. Spitzer images show mid-infrared emission from sources A and C, which is spatially associated with the mm dust continuum emission. No infrared emission is detected from source B, implying that the source is deeply embedded. Based on the morphologies and velocity structure, we propose a hierarchical fragmentation picture for SVS13 where the three sources (A, B, and C) were formed by initial fragmentation of a filamentary prestellar core, while the protobinary system (sources B and VLA3) was formed by rotational fragmentation of a single collapsing sub-core.
In a one-dimensional weak-link wire the spin-orbit interaction (SOI) alone cannot generate a nonzero spin current. We show that a Zeeman field acting in the wire in conjunction with the Rashba SOI there does yield such a current, whose magnitude and direction depend on the direction of the field. When this field is not parallel to the effective field due to the SOI, both the charge and the spin currents oscillate with the length of the wire. Measuring the oscillating anisotropic magnetoresistance can thus yield information on the SOI strength. These features are tuned by applying a magnetic and/or an electric field, with possible applications to spintronics.
We give an algorithm for enumerating the regular nontrivial partial difference sets (PDS) in the group $G_n = C_{2^n}\times C_{2^n}$. We use our algorithm to obtain all of these PDS in $G_n$ for $2\leq n\leq 9$, and we obtain partial results for $n=10$ and $n=11$. Most of these PDS are new. For $n\le 4$ we also identify group-inequivalent PDS. Our approach involves constructing tree diagrams and canonical colorings of these diagrams. Both the total number and the number of group-inequivalent PDS in $G_n$ appear to grow super-exponentially in $n$. For $n=9$, a typical canonical coloring represents in excess of $10^{146}$ group-inequivalent PDS, and there are precisely $2^{520}$ reversible Hadamard difference sets.
The ratios of $p/\pi$ at large transverse momentum in central $Au+Au$ collisions at RHIC are studied in the framework of jet quenching based on a next-to-leading order pQCD parton model. It is shown that theoretical calculations with a gluon energy loss larger than the quark energy loss will naturally lead to a smaller $p/\pi$ ratios at large transverse momentum in $Au+Au$ collisions than those in $p+p$ collisions at the same energy. Scenarios with equal energy losses for gluons and quarks and a strong jet conversion are both explored and it is demonstrated in both scenarios $p/\pi$ ratios at high $p_T$ in central $Au+Au$ collisions are enhanced and the calculated ratios of protons over pions approach to the experimental measurements. However, ${\bar p}/p$ in the latter scenario is found to fit data better than that in the former scenario.
The elephant random walk (ERW) is a microscopic, one-dimensional, discrete-time, non-Markovian random walk, which can lead to anomalous diffusion due to memory effects. In this study, I propose a multi-dimensional generalization in which the probability of taking a step in a certain direction depends on the previous steps in other directions. The original model is generalized in a straightforward manner by introducing coefficients that couple the probability of moving in one direction with the previous steps in all directions. I motivate the model by first introducing a two-elephant system and then elucidating it with a specific coupling. With the explicit calculation of the first moments, I show the existence of two newsworthy relative movement behaviours: one in which one elephant follows the other, and another in which they go in opposite directions. With the aid of a Fokker-Planck equation, the second moment is evaluated and two new super-diffusion regimes appear, not found in other ERWs. Then, I re-interpret the equations as a bidimensional elephant random walk model, and further generalize it to $N-$dimensions. I argue that the introduction of coupling coefficients is a way of extending any one-dimensional ERW to many dimensions.
The solutions for the Tolmann-Oppenheimer-Volkoff (TOV) equation bring valuable informations about the macroscopical features of compact astrophysical objects as neutron stars. They are sensitive to both the equation of state considered for nuclear matter and the background gravitational theory. In this work we construct the TOV equation for a conservative version of the $f(R,T)$ gravity. While the non-vanishing of the covariant derivative of the $f(R,T)$ energy-momentum tensor yields, in a cosmological perspective, the prediction of creation of matter throughout the universe evolution as shown by T. Harko, in the analysis of the hydrostatic equilibrium of compact astrophysical objects, this property still lacks a convincing physical explanation. The imposition of $\nabla^{\mu}T_{\mu\nu}=0$ demands a particular form for the function $h(T)$ in $f(R,T)=R+h(T)$, which is here derived. Therefore, the choice of a specific equation of state for the star matter demands a unique form of $h(T)$, manifesting a strong connection between conserved $f(R,T)$ gravity and the star matter constitution. We construct and solve the TOV equation for the general equation of state for $p=k\rho^{\Gamma}$, with $k$ being the EoS parameter, $\rho$ {\it the energy density} and $\Gamma$ is the adiabatic index. We also derive the macroscopical properties of neutron stars ($\Gamma=5/3$) within this approach.
We study the cosmic peculiar velocity field as traced by a sample of 1184 spiral, elliptical and S0 galaxies, grouped in 704 objects. We carry out a statistical analysis, by calculating bulk flows and velocity correlation functions for this sample and for mock catalogs which we extract from N--body simulations. For the simulations we consider tilted (i.e. with spectral index $n\leq 1$) CDM models with different values of the linear bias parameter $b$. By mean of a maximum likelihood analysis we estimate the ability of the models in fitting the observations as measured by the above statistics and in reproducing the Local Group properties.
We present RoarNet, a new approach for 3D object detection from a 2D image and 3D Lidar point clouds. Based on two-stage object detection framework with PointNet as our backbone network, we suggest several novel ideas to improve 3D object detection performance. The first part of our method, RoarNet_2D, estimates the 3D poses of objects from a monocular image, which approximates where to examine further, and derives multiple candidates that are geometrically feasible. This step significantly narrows down feasible 3D regions, which otherwise requires demanding processing of 3D point clouds in a huge search space. Then the second part, RoarNet_3D, takes the candidate regions and conducts in-depth inferences to conclude final poses in a recursive manner. Inspired by PointNet, RoarNet_3D processes 3D point clouds directly without any loss of data, leading to precise detection. We evaluate our method in KITTI, a 3D object detection benchmark. Our result shows that RoarNet has superior performance to state-of-the-art methods that are publicly available. Remarkably, RoarNet also outperforms state-of-the-art methods even in settings where Lidar and camera are not time synchronized, which is practically important for actual driving environments. RoarNet is implemented in Tensorflow and publicly available with pre-trained models.
Thin films of Ti1-xCoxO2 (x=0 and 0.03) have been prepared on sapphire substrates by spin-on technique starting from metalorganic precursors. When heat treated in air at 550 and 700 C respectively, these films present pure anatase and rutile structures as shown both by X-ray diffraction and Raman spectroscopy. Optical absorption indicate a high degree of transparency in the visible region. Such films show a very small magnetic moment at 300 K. However, when the anatase and the rutile films are annealed in a vacuum of 1x10-5 Torr at 500 oC and 600 oC respectively, the magnetic moment, at 300 K, is strongly enhanced reaching 0.36 B/Co for the anatase sample and 0.68 B/Co for the rutile one. The ferromagnetic Curie temperature of these samples is above 350 K.
We consider the motion of uncharged dust grains of arbitrary shape including the effects of electromagnetic radiation and thermal emission. The resulting relativistically covariant equation of motion is expressed in terms of standard optical parameters. Explicit expressions for secular changes of osculating orbital elements are derived in detail for the special case of the Poynting-Robertson effect. Two subcases are considered: (i) central acceleration due to gravity and the radial component of radiation pressure independent of the particle velocity, (ii) central acceleration given by gravity and the radiation force as the disturbing force. The latter case yields results which may be compared with secular orbital evolution in terms of orbital elements for an arbitrarily shaped dust particle. The effects of solar wind are also presented.
Exclusive semileptonic $B$ decays into excited charmed mesons are studied with QCD sum rules in the leading order of heavy quark effective theory. Two universal Isgur-Wise functions \tau and \zeta for semileptonic B decays into four lowest lying excited $D$ mesons ($D_1$, $D_2^*$, $D'_0$, and $D'_1$) are determined. The decay rates and branching ratios for these processes are calculated.
Using Rindler method we derive the logarithmic correction to the entanglement entropy of a two dimensional BMS-invariant field theory (BMSFT). In particular, we present a general formula for extraction of the logarithmic corrections to both the thermal and the entanglement entropies. We also present a CFT formula related to the logarithmic correction of the BTZ inner horizon entropy which results in our formula after taking appropriate limit.
We present the $UBVRI$ CCD photometry in the region of the open cluster NGC 2421. Radius of the cluster is determined as $\sim$ 3$^\prime$.0 using stellar density profile. Our Study indicates that metallicity of the cluster is $Z \sim$ 0.004. The reddening $E(B-V) = 0.42\pm$0.05 mag is determined using two colour $(U-B)$ versus $(B-V)$ diagram. By combining the 2MASS $JHK$ data with the optical data we determined $E(J-K) = 0.20\pm$0.20 mag and $E(V-K) = 1.15\pm$0.20 mag for this cluster. Colour-excess diagrams show normal interstellar extinction law in the direction of the cluster. We determined the distance of the cluster as 2.2$\pm$0.2 Kpc by comparing the ZAMS with the intrinsic CM diagram of the cluster. The age of the cluster has been estimated as 80$\pm$20 Myr using the stellar isochrones of metallicity $Z = 0.004$. The mass function slope $x = 1.2\pm0.3$ has been derived by applying the corrections of field stars contamination and data incompleteness. Our analysis indicate that the cluster NGC 2421 is dynamically relaxed.
Motivated by an increasing number of remarkable experimental observations on the role of pressure and shear stress in solid reactions,explosions and detonations,we present a simple toy model that embodies nonlinear elasticity and dispersion as well as chemical or phase transformation.This generalization of the Toda Lattice provides an effective model for the description of the organization during an abrupt transformation in a solid.One of the challenges is to capture both the equilibrium degrees of freedom as well as to quantify the possible role of out-of-equilibrium perturbations.In the Toda Lattice,we verify that the particle velocities converge in distribution towards the Maxwell-Boltzmann distribution,thus allowing us to define a bona-fide temperature.In addition,the balance between nonlinearity and wave dispersion may create solitary waves that act as energy traps.In the presence of reactive chemistry,we show that the trapping of the released chemical energy in solitary waves that are excited by an initial perturbation provides a positive feedback that enhances the reaction rate and leads to supersonic explosion front propagation.These modes of rupture observed in our model may provide a first-order description of ultrafast reactions of heterogeneous mixtures under mechanical loading.
Let $L$ be the Euclidean functional with $p$-th power-weighted edges. Examples include the sum of the $p$-th power-weighted lengths of the edges in minimal spanning trees, traveling salesman tours, and minimal matchings. Motivated by the works of Steele, Redmond and Yukich (1994, 1996) have shown that for $n$ i.i.d. sample points $\{X_1,...,X_n\}$ from $[0,1]^d$, $L(\{X_1,...,X_n\})/n^{(d-p)/d}$ converges a.s. to a finite constant. Here we bound the rate of convergence of $EL(\{X_1,...,X_n\})/n^{(d-p)/d}$.
How many fraction of gas available at the outer boundary can finally fall onto the black hole is an important question. It determines the observational appearance of accretion flows, and is also related with the evolution of black hole mass and spin. Previous two-dimensional hydrodynamical simulations of hot accretion flows find that the flow is convectively unstable because of its inward increase of entropy. As a result, the mass accretion rate decreases inward, i.e., only a small fraction of accretion gas can fall onto the black hole, while the rest circulates in the convective eddies or lost in convective outflows. Radiation is usually neglected in these simulations. In many cases, however, radiative cooling is important. In the regime of the luminous hot accretion flow (LHAF), radiative cooling is even stronger than the viscous dissipation. In the one dimensional case, this implies that the inward increase of entropy will become slower or the entropy even decreases inward in the case of an LHAF. We therefore expect that convective instability becomes weaker or completely disappears when radiative cooling is important. To examine the validity of this expectation, in this paper we perform two-dimensional hydrodynamical simulations of hot accretion flows with strong radiative cooling. We find that compared to the case of negligible radiation, convection only becomes slightly weaker. Even an LHAF is still strongly convectively unstable, its radial profile of accretion rate correspondingly changes little. We find the reason is that the entropy still increases inward in the two-dimensional case.
We explain how A. Givental's mirror symmetric family to the type A flag variety and its proposed generalization to partial flag varieties by Batyrev, Ciocan-Fontanine, Kim and van Straten relate to the Peterson variety Y in SL_n/B. We then use this theory to describe the totally nonnegative part of Y.
Ramanujan sums have been studied and generalized by several authors. For example, Nowak studied these sums over quadratic number fields, and Grytczuk defined that on semigroups. In this note, we deduce some properties on sums of generalized Ramanujan sums and give examples on number fields. In particular, we have a relational expression between Ramanujan sums and residues of Dedekind zeta functions.
We present the analysis of the spin vector orientation of 5$\,$987 SDSS galaxies having negative redshift from $-$87.6 to $-$0.3 km$\,$s$^{-1}$. Two dimensional observed parameters are used to compute three dimensional galaxy rotation axes by applying `position angle--inclination' method. We aim to examine the non-random effects in the spatial orientation of blue-shifted galaxies. We generate 5$\times$10$^6$ virtual galaxies to find expected isotropic distributions by performing numerical simulations. We have written MATLAB program to facilitate the simulation process and eliminate the manual errors in the process. Chi-square, auto-correlation, and the Fourier tests are used to examine non-random effects in the polar and azimuthal angle distributions of the galaxy rotation axes. In general, blue-shifted galaxies show no preferred alignments of galaxy rotation axes. Our results support Hierarchy model, which suggests a random orientation of angular momentum vectors of galaxies. However, local effects are noted suggesting gravitational tidal interaction between neighboring galaxies.
We develop the theory of continuous-variable quantum secret sharing and propose its interferometric realization using passive and active optical elements. In the ideal case of infinite squeezing, a fidelity ${\cal F}$ of unity can be achieved with respect to reconstructing the quantum secret. We quantify the reduction in fidelity for the (2,3) threshold scheme due to finite squeezing and establish the condition for verifying that genuine quantum secret sharing has occurred.
Herein is presented a research with regard to the calculation of quantum mean values, for a composite A+B, by using different formulas to expressions in Boltzmann-Gibbs-Shannon's statistics. It is analyzed why matrix formulas E_A y E_B, in Hilbert subspaces, produce identical results to full Hilbert space formulas. In accord to former investigations, those matrices are the adequated density matrices, inside third version of nonextensive statistical mechanics. Those investigations were obtained by calculating the thermodynamical parameters of magnetization and internal energy. This publication demonstrates that it is not necessary postulate the mean values formulas in Hilbert subspaces, but they can be stem from full Hilbert space, taking into consideration the statistical independence concept.
It is shown how the electromagnetic response of the 2DEG under Quantumm Hall Effect regime, chracterized by the Chern-Simons topological action, transforms the sample impurities and defects in charge reservoirs that stabilize the the Hall conductivity plateaus. The results, determine the basic dynamical origin of the singular properties of localization under the occurrence of the QHE obtained in the pioneering works of Laughlin and of Joynt and Prange, by means of a gauge invariance argument and a purely electronic analysis, respectively. The common picture of electrons moving the equipotential lines gets an analytical realization through the Chern-Simons current and charge densities.
Non-periodic tilings of $\mathbb{Z}_N$ are a difficult to obtain key to a wide range of complex mathematical issues. In a musician's eyes, they are called rhythmic Vuza canons. After a short summary of the main properties of rhythmic tiling canons and after stressing the importance of Vuza canons, this article presents a new approach: modulo $p$ Vuza canons. Working modulo $p$ (especially with $p=2$) allows Vuza canons to be computed very quickly. But going back to traditional Vuza canons requires understanding of when and how the tiling is a covering. The article's main result is a complete case construction of a modulo $2$ tiling. This first solution of a modulo $2$ tiling is proved in a constructive way, which, it is hoped, is expandable to every modulo $p$ tiling. Following this path may lead to a solution to the problem of building modulo $p$ tilings and thus a solution to the problem of easily finding traditional Vuza canons.
We apply improved elliptic regularity results to a concrete symmetric Dirichlet form and various non-symmetric Dirichlet forms with possibly degenerate symmetric diffusion matrix. Given the (non)-symmetric Dirichlet form, using elliptic regularity results and stochastic calculus we show weak existence of the corresponding singular stochastic differential equation for any starting point in some subset E of R^d. As an application of our approach we can show the existence of n-regularized Liouville Brownian motion only via Dirichlet form theory starting from all points in R^2.
If H and D are two orders in a central simple algebra A with D of maximal rank and containing H, the theory of representation fields describes the set of spinor genera of orders in the genus of D representing the order H. When H is contained in a maximal subfield of A and the dimension of A is the square of a prime p, the proportion of spinor genera representing H has the form r/p, in fact, when the representation field exists, this proportion is either 1 or 1/p. In the later case the order H is said to be selective for the genus. The condition for selectivity is known when D is maximal and also when p = 2 and D is an Eichler order. In this work we describe the orders H that are selective for at least one genus of orders of maximal rank in A.
We present multi-band photometric and spectroscopic observations of the type II supernova, (SN) 2019va, which shows an unusually flat plateau-phase evolution in its V-band light curve. Its pseudo-bolometric light curve even shows a weak brightening towards the end of the plateau phase. These uncommon features are related to the influence of 56Ni decay on the light curve during the plateau phase, when the SN emission is usually dominated by cooling of the envelope. The inferred 56Ni mass of SN 2019va is 0.088+/-0.018 solar mass, which is significantly larger than most SNe II. To estimate the influence of 56Ni decay on the plateau-phase light curve, we calculate the ratio (dubbed as eta_Ni) between the integrated time-weighted energy from 56Ni decay and that from envelope cooling within the plateau phase, obtaining a value of 0.8 for SN 2019va, which is the second largest value among SNe II that have been measured. After removing the influence of 56Ni decay on the plateau-phase light curve, we found that the progenitor/explosion parameters derived for SN 2019va are more reasonable. In addition, SN 2019va is found to have weaker metal lines in its spectra compared to other SNe IIP at similar epochs, implying a low-metallicity progenitor, which is consistent with the metal-poor environment inferred from the host-galaxy spectrum. We further discuss the possible reasons that might lead to SN 2019va-like events.
A spin-isospin dependent three-dimensional approach has been applied for formulation of the three-nucleon bound state and a new expression for Faddeev equation based on three-nucleon free basis state has been obtained. Then the three-nucleon wave function has been obtained as a function of five independent variables.
We consider the efficiency at maximum power of a quantum Otto engine, which uses a spin or a harmonic system as its working substance and works between two heat reservoirs at constant temperatures $T_h$ and $T_c$ $ (<T_h)$. Although the spin-$1/2$ system behaves quite differently from the harmonic system in that they obey two typical quantum statistics, the efficiencies at maximum power based on these two different kinds of quantum systems are bounded from the upper side by the same expression of the efficiency at maximum power: $\eta_{mp}\leq\eta_+\equiv \eta_C^2/[\eta_C-(1-\eta_C)\ln(1-\eta_C)]$, with $\eta_C=1-T_c/T_h$ the Carnot efficiency, which displays the same universality of the CA efficiency $\eta_{CA}=1-\sqrt{1-\eta_C}$ at small relative temperature difference. Within context of irreversible thermodynamics, we calculate the Onsager coefficients and, we show that the value of $\eta_{CA}$ is indeed the upper bound of EMP for the Otto engines working in the linear-response regime.