ShantanuT01/DACTYL-Pretraining huggingface dataset:
We argue a new classification scheme of long gamma-ray bursts (LGRBs) using the morphology of the cumulative light curve of the prompt emission. We parametrize the morphology by the absolute deviation from their constant luminosity ($ADCL$) and derive the value for 36 LGRBs which have spectropic redshifts, spectral parameters determined by the Band model, 1-second peak fluxes, fluences, and 64-msec resolution light curves whose peak counts are 10 times larger than background fluctuations. Then we devide the sample according to the value of ADCL into two groups ($ADCL < 0.17$ and $ADCL > 0.17$) and, for each group, derive the spectral peak energy $E_{\rm p}$ - peak luminosity $L_{\rm p}$ correlation and the Fundamental Plane of LGRBs, which is a correlation between the spectral peak energy $E_{\rm p}$, the luminosity time $T_{\rm L}$ ($\equiv E_{\rm iso}/L_{\rm p}$ where $E_{\rm iso}$ is isotropic energy) and the peak luminosity $L_{\rm p}$. We find that both of the correlations for both groups are statistically more significant compared with ones derived from all samples. The Fundamental Planes with small and large ADCL are given by $L_{\rm p}=10^{52.53\pm 0.01}(E_{\rm p}/10^{2.71}{\rm keV})^{1.84\pm 0.03} (T_{\rm L}/10^{0.86}{\rm sec})^{0.29\pm0.08}$ with $\chi^2_{\nu}=10.93/14$ and $L_{\rm p}=10^{52.98\pm0.08}(E_{\rm p}/10^{2.71}{\rm keV})^{1.82\pm 0.09} (T_{\rm L}/10^{0.86}{\rm sec})^{0.85\pm 0.27}$ with $\chi^2_{\nu}=7.58/8$, respectively. This fact implies the existence of subclasses of LGRBs characterized by the value of $ADCL$. Also there is a hint for the existence of the intermediate-$ADCL$ class which deviates from both fundamental planes. Both relations are so tight that our result provides a new accurate distance measurement scheme up to the high redshift universe.
We start from the polynomic interatomic potentials introduced by Wojde{\l} et al. [J. Phys. Condens. Matt. 25, 305401(2013)] and take advantage of one of their key features -- namely, the linear dependence of the energy on the potential's adjustable parameters -- to devise a scheme for the construction of first-principles-based ({\em second-principles}) models for large-scale lattice-dynamical simulations. Our method presents the following convenient features. The parameters of the model are computed in a very fast and efficient way, as it is possible to recast the fit to a training set of first-principles data into a simple matrix diagonalization problem. Our method selects automatically the interactions that are most relevant to reproduce the training-set data, by choosing from a pool that includes virtually all possible coupling terms, and produces a family of models of increasing complexity and accuracy. We work with practical and convenient cross-validation criteria linked to the physical properties that will be relevant in future simulations based on the new model, and which greatly facilitate the task of identifying a potential that is simultaneously simple (thus computationally light), very accurate, and predictive. We also discuss practical ways to guarantee that our energy models are bounded from below, with a minimal impact on their accuracy. Finally, we demonstrate our scheme with an application to ferroelastic perovskite SrTiO$_{3}$, which features many non-trivial lattice-dynamical features (e.g., a phase transition driven by soft phonons, competing structural instabilities, highly anharmonic dynamics) and provides a very demanding test.
The neck dynamics in Fermi-energy heavy-ion collisions, to probe the nuclear symmetry energy in the domain of sub-saturation densities, is investigated within an isospin dependent transport model. The single and double ratios of neutron/proton from free nucleons and light clusters (complex particles) in the isotopic reactions are analyzed systematically. Isospin effects of particles produced from the neck fragmentations are explored, which are constrained within the midrapidities ($|y/y_{proj}|<$0.3) and azimuthal angles (70$^{o}\sim$110$^{o}$, 250$^{o}\sim$290$^{o}$) in semiperipheral nuclear collisions. It is found that the ratios of the energetic isospin particles strongly depend on the stiffness of nuclear symmetry energy and the effects increase with softening the symmetry energy, which would be a nice probe for extracting the symmetry energy below the normal density in experimentally. A flat structure appears at the tail spectra from the double ratio distributions. The neutron to proton ratio of light intermediate mass fragments (IMFs) with charged number Z$\leq$8 is related to the density dependence of symmetry energy with less sensitivity in comparison to the isospin ratios of nucleons and light particles.
We summarize recent work showing how the Thermodynamic Bethe Ansatz may be used to study the finite-density first-order phase transition in the Gross-Neveu model. The application to trans-polyacetylene is discussed, and the significance of the results is addressed.
NGC 1052-DF2, an ultra diffuse galaxy (UDG), has been the subject of intense debate. Its alleged absence of dark matter, and the brightness and number excess of its globular clusters (GCs) at an initially assumed distance of 20Mpc, suggested a new formation channel for UDGs. We present the first systematic spectroscopic analysis of both the stellar body and the GCs (six of which were previously known, and one newly confirmed member) of this galaxy using MUSE@VLT. Even though NGC 1052-DF2 does not show any spatially extended emission lines we report the discovery of three planetary nebulae (PNe). We conduct full spectral fitting on the UDG and the stacked spectra of all GCs. The UDG's stellar population is old, 8.9$\pm$1.5 Gyr, metal-poor, with [M/H] = $-$1.07$\pm$0.12 with little or no $\alpha$-enrichment. The stacked spectrum of all GCs indicates a similar age of 8.9$\pm$1.8 Gyr, but lower metallicity, with [M/H] = $-$1.63$\pm$0.09, and similarly low $\alpha$-enrichment. There is no evidence for a variation of age and metallicity in the GC population with the available spectra. The significantly more metal-rich stellar body with respect to its associated GCs, the age of the population, its metallicity and alpha enrichment, are all in line with other dwarf galaxies. NGC 1052-DF2 thus falls on the same empirical mass-metallicity relation as other dwarfs, for the full distance range assumed in the literature. We find that both debated distance estimates (13 and 20 Mpc) are similarly likely, given the three discovered PNe.
We present the first numerical simulations of an initially non-spinning black-hole binary with mass ratio as large as 10:1 in full general relativity. The binary completes approximately 3 orbits prior to merger and radiates about 0.415% of the total energy and 12.48% of the initial angular momentum in the form of gravitational waves. The single black hole resulting from the merger acquires a kick of about 66.7 km/s relative to the original center of mass frame. The resulting gravitational waveforms are used to validate existing formulas for the recoil, final spin and radiated energy over a wider range of the symmetric mass ratio parameter eta=M1*M2/(M1+M2)^2 than previously possible. The contributions of l > 2 multipoles are found to visibly influence the gravitational wave signal obtained at fixed inclination angles.
A {\it tiered graph} $G=(V,E)$ with $m $ tiers is a simple graph with $V\subseteq \brk{n}$, where $\brk{n}=\{1,2,\cdots,n\}$, and with a surjective map $t$ from $V$ to $\brk{m}$ such that if $v$ is a vertex adjacent to $v'$ in $G$ with $v>v'$, then $t(v) >t(v')$. For any ordered partition $p=(p_1,p_2,\cdots,p_m)$ of $n$, let $\sett_p$ denote the set of tiered trees with vertex set $\brk{n}$ and with a map $t: \brk{n}\rightarrow \brk{m}$ such that $|t^{-1}(i)|=p_i$ for all $i=1,2,\ldots,m$. For any $T\in \sett_p$, let $K_T$ denote the complete tiered graph whose vertex set and tiering map are the same as those of $T$. If the edges of $K_T$ are ordered lexicographically by their endpoints, then the weight $w(T)$ of $T$ is the external activity of $T$ in $K_T$, i.e., the number of edges $e\in E(K_{T})\setminus E(T)$ such that $e$ is the least element in the unique cycle determined by $T\cup e$. Let $P_p(q)=\sum_{T\in \sett_{p}}q^{w(T)}$. Dugan, Glennon, Gunnells and Steingr\'imsson [J. Combin. Theory, Ser. A 164 (2019) pp. 24-49] asked for an elementary proof of the identity $P_p(q)=P_{\pi(p)}(q)$ for any permutation $\pi$ of $1,2,\cdots,m$, where $\pi(p)=p_{\pi(1)},p_{\pi(2)},\cdots,p_{\pi(m)})$. In this article, we will prove an extension of this identity by applying Tutte polynomials. Furthermore, we also provide a proof of the identity $P_{(1,p_1,p_2)}(q)=P_{(p_1+1,p_2+1)}(q)$ via Tutte polynomials.
We establish conditions under which the experimental verification of quantum error-correcting behavior against a linear set of error operators $\ce$ suffices for the verification of noiseless subsystems of an error algebra $\ca$ contained in $\ce$. From a practical standpoint, our results imply that the verification of a noiseless subsystem need not require the explicit verification of noiseless behavior for all possible initial states of the syndrome subsystem.
Covalent organic frameworks (COFs) have attracted significant attention due to their chemical versatility combined with a significant number of potential applications. Of particular interest are two-dimensional COFs, where the organic building units are linked by covalent bonds within a plane. Most properties of these COFs are determined by the relative arrangement of neighboring layers. These are typically found to be laterally displaced, which, for example, reduces the electronic coupling between the layers. In the present contribution, we use dispersion-corrected density-functional theory to elucidate the origin of that displacement, showing that the common notion that the displacement is a consequence of electrostatic repulsions of polar building blocks can be misleading. For the representative case of COF-1, we find that electrostatic and van der Waals interactions would, actually, favor a cofacial arrangement of the layers and that Pauli repulsion is the crucial factor causing the serrated AA stacking. A more in-depth analysis of the electrostatic contribution reveals that the "classical" Coulomb repulsion between the boroxine building blocks of COF-1 suggested by chemical intuition does exist, but is overcompensated by attractive effects due to charge-penetration in the phenylene units. The situation becomes more involved when additionally allowing the interlayer distance to relax for each displacement, as then the different distance-dependences of the various types of interactions come into play. The overall behavior calculated for COF-1 is recovered for several additional COFs with differently sized pi-systems and topologies, implying that the presented results are of more general relevance.
Let A be an abelian variety of positive dimension defined over a number field K and let Kbar be a fixed algebraic closure of K. For each element sigma of the absolute Galois group Gal(Kbar/K), let Kbar(sigma) be the fixed field of sigma in Kbar. We shall prove that the torsion subgroup of A(Kbar(sigma)) is infinite for all sigma in Gal(Kbar/K) outside of some set of Haar measure zero. This proves the number field case of a conjecture of Geyer and Jarden from 1978.
We discuss the implications of using an intrinsic Hamiltonian in theories without particle-number conservation, e.g., the Hartree-Fock-Bogoliubov approximation, where the Hamiltonian's particle-number dependence leads to discrepancies if one naively replaces the particle-number operator by its expectation value. We develop a systematic expansion that fixes this problem and leads to an a posteriori justification of the widely-used one- plus two-body form of the intrinsic kinetic energy in nuclear self-consistent field methods. The expansion's convergence properties as well as its practical applications are discussed for several sample nuclei.
We present the observed/intrinsic optical parameters and the variability analysis of the Naked-Eye Burst, GRB 080319B, observed by the TORTORA wide-field optical monitoring system. The event is extreme not only in observed properties but also intrinsically: it is the most luminous event ever recorded at optical wavelengths. The temporal properties suggest short-lived periodic activities of the internal engine. This is the fastest optically variable source detected at cosmological distances.
We prove the existence of a principal eigenvalue associated to the $\infty$-Laplacian plus lower order terms and the Neumann boundary condition in a bounded smooth domain. As an application we get uniqueness and existence results for the Neumann problem and a decay estimate for viscosity solutions of the Neumann evolution problem.
The partition number $\pi(K)$ of a simplicial complex $K\subset 2^{[n]}$ is the minimum integer $\nu$ such that for each partition $A_1\uplus\ldots\uplus A_\nu = [n]$ of $[n]$ at least one of the sets $A_i$ is in $K$. A complex $K$ is $r$-unavoidable if $\pi(K)\leq r$. Motivated by the problems of Tverberg-Van Kampen-Flores type, and inspired by the `constraint method' of Blagojevi\'{c}, Frick, and Ziegler, arXiv:1401.0690 [math.CO], we study the combinatorics of $r$-unavoidable complexes.
We study the one-dimensional Riemann problem for a hyperbolic system of three conservation laws of Temple class. This systems it is a simplification of a recently propose system of five conservations laws by Bouchut and Boyaval that model viscoelastic fluids. An important issues is that the considered $3 \times 3$ system is such that every characteristic field is linearly degenerate. We show the Riemann problem for this system. Under suitable generalized Rankine-Hugoniot relation and entropy condition, both existence and uniqueness of particular delta-shock type solutions are established.
We argue that the Anderson and Kondo models turn out to be irrelevant for the description of some strongly correlated electron systems and we suggest the mechanism for the formation of many-body states (heavy fermions) being an alternative to the Kondo one. This mechanism involves the quantum tunneling of a heavy particle between the states in the double-well potential.
We address the problem of the so-called ``granular gases'', i.e. gases of massive particles in rapid movement undergoing inelastic collisions. We introduce a class of models of driven granular gases for which the stationary state is the result of the balance between the dissipation and the random forces which inject energies. These models exhibit a genuine thermodynamic limit, i.e. at fixed density the mean values of kinetic energy and dissipated energy per particle are independent of the number $N$ of particles, for large values of $N$. One has two regimes: when the typical relaxation time $\tau$ of the driving Brownian process is small compared with the mean collision time $\tau_c$ the spatial density is nearly homogeneous and the velocity probability distribution is gaussian. In the opposite limit $\tau \gg \tau_c$ one has strong spatial clustering, with a fractal distribution of particles, and the velocity probability distribution strongly deviates from the gaussian one. Simulations performed in one and two dimensions under the {\it Stosszahlansatz} Boltzmann approximation confirm the scenario. Furthermore we analyze the instabilities bringing to the spatial and the velocity clusterization. Firstly, in the framework of a mean-field model, we explain how the existence of the inelasticity can bring to a spatial clusterization; on the other side we discuss, in the framework of a Langevin dynamics treating the collisions in a mean-field way, how a non-gaussian distribution of velocity can arise. The comparison between the numerical and the analytical results exhibits an excellent agreement.
We explore the amplification of magnetic seed fields during the formation of the first stars and galaxies. During gravitational collapse, turbulence is created from accretion shocks, which may act to amplify weak magnetic fields in the protostellar cloud. Numerical simulations showed that such turbulence is sub-sonic in the first star-forming minihalos, and highly supersonic in the first galaxies with virial temperatures larger than 10^4 K. We investigate the magnetic field amplification during the collapse both for Kolmogorov and Burgers-type turbulence with a semi-analytic model that incorporates the effects of gravitational compression and small-scale dynamo amplification. We find that the magnetic field may be substantially amplified before the formation of a disk. On scales of 1/10 of the Jeans length, saturation occurs after ~10^8 yr. Although the saturation behaviour of the small-scale dynamo is still somewhat uncertain, we expect a saturation field strength of the order ~10^{-7} n^{0.5} G in the first star-forming halos, with n the number density in cgs units. In the first galaxies with higher turbulent velocities, the magnetic field strength may be increased by an order of magnitude, and saturation may occur after 10^6 to 10^7 yr. In the Kolmogorov case, the magnetic field strength on the integral scale (i.e. the scale with most magnetic power) is higher due to the characteristic power-law indices, but the difference is less than a factor of 2 in the saturated phase. Our results thus indicate that the precise scaling of the turbulent velocity with length scale is of minor importance. They further imply that magnetic fields will be significantly enhanced before the formation of a protostellar disk, where they may change the fragmentation properties of the gas and the accretion rate.
We compute black hole masses and bolometric luminosities for 57 active galactic nuclei (AGN) in the redshift range 1.25 < z < 2.67, selected from the GOODS-South deep multi-wavelength survey field via their X-ray emission. We determine host galaxy morphological parameters by separating the galaxies from their central point sources in deep HST images, and host stellar masses and colors by multi-wavelength SED fitting. 90% of GOODS AGN at these redshifts have detected rest-frame optical nuclear point sources; bolometric luminosities range from 2e43 - 2e46 erg/s. The black holes are growing at a range of accretion rates, with at least 50% of the sample having L/L_Edd < 0.1. 70% of host galaxies have stellar masses M* > 1e10 M_sun, with a range of colors suggesting a complex star formation history. We find no evolution of AGN bolometric luminosity within the sample, and no correlation between AGN bolometric luminosity and host stellar mass, color or morphology. Fully half the sample of host galaxies is disk-dominated, with another 25% having strong disk components. Fewer than 15% of the systems appear to be at some stage of a major merger. These moderate-luminosity AGN hosts are therefore inconsistent with a dynamical history dominated by mergers strong enough to destroy disks, indicating minor mergers or secular processes dominate the co-evolution of galaxies and their central black holes at z ~ 2.
Double-trace deformations of the AdS/CFT duality result in a new perturbation expansion for string theory, based on a non-local worldsheet. We discuss some aspects of the deformation in the low energy gravity approximation, where it appears as a change in the boundary condition of fields. We relate unique features of the boundary of AdS to the worldsheet becoming non-local, and conjecture that non-local worldsheet actions may be generic in other classes of backgrounds.
We study the thermal equilibrium of nonlinear Klein-Gordon chains at the limit of small coupling (anticontinuum limit). We show that the persistence distribution associated to the local energy density is a useful tool to study the statistical distribution of so-called thermal breathers, mainly when the equilibrium is characterized by long-lived static excitations; in that case, the distribution of persistence intervals turns out to be a powerlaw. We demonstrate also that this generic behaviour has a counterpart in the power spectra, where the high frequencies domains nicely collapse if properly rescaled. These results are also compared to non linear Klein-Gordon chains with a soft nonlinearity, for which the thermal breathers are rather mobile entities. Finally, we discuss the possibility of a breather-induced anomalous diffusion law, and show that despite a strong slowing-down of the energy diffusion, there are numerical evidences for a normal asymptotic diffusion mechanism, but with exceptionnally small diffusion coefficients.
We present a concrete and consistent procedure to generate one kind of non-perturbative superpotential, including the gaugino condensation corrections and poly-instanton corrections, in type IIB orientifold compactification with four Kahler Moduli. Then we use this kind of superpotential as well as the alphaprime-corrections to Kahler potential to fix all of the four Kahler moduli on a general Calabi-Yau manifold with typical K3-fibred volume form. In our construction, the considered Calabi-Yau threefolds are K3-fibred and admit at least one del Pezzo surface and one W-surface. Searching through all existing four dimensional reflexive lattice polytopes, we find 23 of them fulfilling all the requirements.
Coronal bright points (CBPs) as characteristics of the solar corona are small-scale bright features ubiquitously observed at extreme ultraviolet passbands. Here, we focused on time series of CBPs in the periods of their lifetimes. We used Solar Dynamic Observatory (SDO) / Atmospheric Imaging Assembly (AIA) taken at 171 and 193 \AA. Using image processing methods, CBPs were extracted from data and tracked during their lifetimes. We found that CBPs observed in 171 \AA have more lifetimes than those of observed at 193 \AA. CBPs at 171 \AA are more fluctuated in intensity and appeared as highly density number (DN) features than 193 \AA CBPs. It was found that about $75 \%$ of CBPs are firstly achieved their peak at 171 \AA, and then, after 12 seconds two minutes are achieved to their peak at 193 \AA. Computing Pearson correlation for time series of CBPs at both wavelengths where the correlation reaches at maximum value gives information about time delay of magnetic reconnection about 40 seconds from one layer to the other one.
The problem of determining a metal's Fermi surface from measurements of projections of the electron or electron/positron momentum densities, such as obtained by Compton Scattering or Angular Correlation of Positron Annihilation Radiation, respectively, is considered in a Bayesian formulation. A consistent approach is presented and its advantages compared to previous practice is discussed. A validation of the proposed method on simulated data shows its systematic accuracy to be very satisfactory and its statistical precision on modest experimental data to be surprisingly good.
The quantum molecular dynamics model has been improved to investigate the reaction dynamics induced by antiprotons. The reaction channels of elastic scattering, annihilation, charge exchange and inelastic collisions have been included in the model. Dynamics on particle production, in particular pions, kaons, antikaons and hyperons, is investigated in collisions of $\overline{p}$ on $^{12}$C, $^{20}$Ne, $^{40}$Ca, $^{112}$Sn, $^{181}$Ta, $^{197}$Au and $^{238}$U from a low to high incident momentum. The rapidity and momentum distributions of $\pi^{+}$ and protons from the LEAR measurements can be well reproduced. The impacts of system size and incident momentum on particle emissions are investigated from the inclusive spectra, transverse momentum and rapidity distributions. It is found that the annihilations of $\overline{p}$ on nucleons are of importance on the particle production. Hyperons are mainly produced via meson induced reactions on nucleons and strangeness exchange collisions when the incident momentum is below the threshold value of annihilation reaction. A higher nuclear temperature is obtained from the kaon emission, but it has a lower value for hyperon production.