ShantanuT01/DACTYL-Pretraining huggingface dataset:
The GeV$-$TeV $\gamma-$ray line signal is the smoking gun signature of the dark matter annihilation or decay. The detection of such a signal is one of the main targets of some space-based telescopes, including Fermi-LAT and the upcoming CALET, DAMPE and Gamma-400. An important feature of the dark-matter-annihilation originated $\gamma-$ray line photons is their concentration at the center of the Galaxy. So far no reliable $\gamma-$ray line has been detected by Fermi-LAT and the upper limits on the cross section of annihilation into $\gamma-$rays have been reported. We use these upper limits to estimate the "maximal" number of $\gamma-$ray line photons detectable for Fermi-LAT, DAMPE and Gamma-400 and then investigate the spatial distribution of these photons. We show that usually the center of the distribution region will be offset from the Galactic centre (Sgr A$^{\star}$) due to the limited statistics. Such a result is almost independent of the dark matter distribution models and renders the reconstruction of the dark matter distribution with the $\gamma-$ray line signal very challenging for the foreseeable space-based detectors.
We study bond and spin correlations of the nearest-neighbour resonating valence bond (RVB) wavefunction for a SU($2$) symmetric $S=1/2$ antiferromagnet on the honeycomb lattice. We find that spin correlations in this wavefunction are short-ranged, while the bond energy correlation function takes on an oscillatory power-law form $D(\vec{r}) \sim \cos({\mathbf Q}\cdot {\vec{r}}) /|{\vec{r}}|^{\eta_w(2)}$, where ${\mathbf Q} = (2\pi/3, -2\pi/3)$ is the wavevector corresponding to "columnar" valence-bond solid order on the honeycomb lattice, and $\eta_w(2) \approx 1.49(3)$. We use a recently introduced large-$g$ expansion approach to relate bond-energy correlators of the SU($g$) wavefunction to dimer correlations of an interacting fully-packed dimer model with a three-dimer interaction of strength $V(g)=-\log(1+1/g^2)$. Putting $g=2$, we find numerically that the dimer correlation function $D^{d}(\vec{r})$ of this dimer model has power-law behaviour $D^{d}(\vec{r}) \sim \cos({\mathbf Q}\cdot {\vec{r}}) /|{\vec{r}}|^{\eta_d(2)}$ with $\eta_d(2) \approx 1.520(15)$, in rather good agreement with the wavefunction results. We also study the same quantities for $g=3,4,10$ and find that the bond-energy correlations in the SU($g$) wavefunction are consistently well-reproduced by the corresponding dimer correlations in the interacting dimer model.
We add a suite of chemical abundances to the MACER (Massive AGN Controlled Ellipticals Resolved) 2D code, by solving 12 additional continuity equations for H, He, C, N, O, Ne, Mg, Si, S, Ca, Fe and Ni respectively with sources from AGB stars and supernovae of type Ia and II with metal yields based on standard stellar physics. New stars, formed in Toomre unstable circumnuclear disks (of a size $\lesssim150$ parsec), are assumed to have a top-heavy initial mass function with a power index of 1.65. The metal dilution effects due to cosmic accretion are also included. With the high resolution of few parsecs in central regions, resolved black hole accretion and AGN feedback, we can track the metal enrichment, transportation and dilution throughout the modeled massive elliptical galaxy of velocity dispersion $\sim280$ km/s. We retrieve the chemical composition of the BAL winds launched by the central AGN, synthesize the X-ray features of the hot ISM, and find that (1) the simulated metallicity in the BAL winds could be up to $\sim 8 Z_\odot$, while that of the hot ISM in the host galaxy is $\sim 2.3 Z_\odot$, matching well with SDSS observations of BLR gas; (2) the X-ray emitting hot gas is metal enriched with a typical value $\sim2.5 Z_\odot$; (3) the circumunuclear cold gas disk, where the metals are condensed, further enriched and recycled, plays a critical role in the metal enrichment; (4) the black hole accretion rate $\dot{M}_{\rm BH}$ linearly correlates with the star formation rate $\dot{M}_\star^+$ in the circumnuclear disk, i.e, $\dot{M}_\star^+ \sim 7.7 \dot{M}_{\rm BH}$, but lagged in time by roughly $10^6$ years.
We present the study of a quantum Controlled-Controlled-Not gate, implemented in a chain of three nuclear spins weakly Ising interacting between all of them, that is, taking into account first and second neighbor spin interactions. This implementation is done using a single resonant $\pi$-pulse on the initial state of the system (digital and superposition). The fidelity parameter is used to determine the behavior of the CCN quantum gate as a function of the ratio of the second neighbor interaction coupling constant to the first neighbor interaction coupling constant ($J'/J$). We found that for $J'/J\ge 0.02$ we can have a well defined CCN quantum gate.
We show that the dynamics of disordered charge density waves (CDWs) and spin density waves (SDWs) is a collective phenomenon. The very low temperature specific heat relaxation experiments are characterized by: (i) ``interrupted'' ageing (meaning that there is a maximal relaxation time); and (ii) a broad power-law spectrum of relaxation times which is the signature of a collective phenomenon. We propose a random energy model that can reproduce these two observations and from which it is possible to obtain an estimate of the glass cross-over temperature (typically $T_g \simeq 100 - 200$ mK). The broad relaxation time spectrum can also be obtained from the solutions of two microscopic models involving randomly distributed solitons. The collective behavior is similar to domain growth dynamics in the presence of disorder and can be described by the dynamical renormalization group that was proposed recently for the one dimensional random field Ising model [D.S. Fisher, P. Le Doussal and C. Monthus, Phys. Rev. Lett. {\bf 80}, 3539 (1998)]. The typical relaxation time scales like $\tau^{\rm typ} \sim \tau_0 \exp{(T_g/T)}$. The glass cross-over temperature $T_g$ related to correlations among solitons is equal to the average energy barrier and scales like $T_g \sim 2 x \xi_0 \Delta$. $x$ is the concentration of defects, $\xi_0$ the correlation length of the CDW or SDW and $\Delta$ the charge or spin gap.
We present a sequence of 12 monthly polarimetric 15, 22, and 43 GHz VLBA observations of the radio galaxy 3C 120 revealing a systematic presence of gradients in Faraday rotation and degree of polarization across and along the jet. The degree of polarization increases with distance from the core and toward the jet edges, and has an asymmetric profile in which the northern side of the jet is more highly polarized. The Faraday rotation measure is also stratified across the jet width, with larger values for the southern side. We find a localized region of high Faraday rotation measure superposed on this structure between approximately 3 and 4 mas from the core, with a peak of about 6000 rad/m^2. Interaction of the jet with the external medium or a cloud would explain the confined region of enhanced Faraday rotation, as well as the stratification in degree of polarization and the flaring of superluminal knots when crossing this region. The data are also consistent with a helical field in a two-fluid jet model, consisting of an inner, emitting jet and a sheath containing nonrelativistic electrons. However, this helical magnetic field model cannot by itself explain the localized region of enhanced Faraday rotation. The polarization electric vectors, predominantly perpendicular to the jet axis once corrected for Faraday rotation, require a dominant component parallel to the jet axis (in the frame of the emitting plasma) for the magnetic field in the emitting region.
For $1<\alpha <2$ we derive the asymptotic distribution of the total length of {\em external} branches of a Beta$(2-\alpha, \alpha)$-coalescent as the number $n$ of leaves becomes large. It turns out the fluctuations of the external branch length follow those of $\tau_n^{2-\alpha}$ over the entire parameter regime, where $\tau_n$ denotes the random number of coalescences that bring the $n$ lineages down to one. This is in contrast to the fluctuation behavior of the total branch length, which exhibits a transition at $\alpha_0 = (1+\sqrt 5)/2$.
The optimal entanglement manipulation for a single copy of mixed states of two qubits is to transform it to a Bell diagonal state. In this paper we derive an explicit form of the local operation that can realize such a transformation. The result obtained is universal for arbitrary entangled two-qubit states and it discloses that the corresponding local filter is not unique for density matrices with rank $n=2$ and can be exclusively determined for that with $n=3$ and 4. As illustrations, a four-parameters family of mixed states are explored, the local filter as well as the transformation probability are given explicitly, which verify the validity of the general result.
Two key reactions of hydrostatic nuclear burning in stars have recently been revised by new experimental data - the 14N(p,gamma)15O and triple alpha reaction rates. We investigate how much the new rates influence the evolution of low-mass, metal-poor and metal-free, stars and of an intermediate-mass star of solar-type composition. We concentrate on phases of helium ignition or thermally unstable helium burning. Our global result is that the new triple alpha rate has no significant influence on such stars, but that there is a noticable, though small, effect of the new 14N(p,gamma)15O rate, in particular on the core helium flash and the blue loop during core helium burning in the intermediate-mass star.
We present a theory of time-dependent tunneling between a metal and a partially spin-polarized two-dimensional electron system (2DES). We find that the leakage current which flows to screen an electric field between the metal and the 2DES is the sum of two exponential contributions whose relative weights depend on spin-dependent tunneling conductances, on quantum corrections to the electrostatic capacitance of the tunnel junction, and on the rate at which the 2DES spin-polarization approaches equilibrium. For high-mobility and homogeneous 2DES's at Landau level filling factor $\nu=1$, we predict a ratio of the fast and slow leakage rates equal to $(2K+1)^2$ where $K$ is the number of reversed spins in the skyrmionic elementary charged excitations.
Training a good deep learning model often requires a lot of annotated data. As a large amount of labeled data is typically difficult to collect and even more difficult to annotate, data augmentation and data generation are widely used in the process of training deep neural networks. However, there is no clear common understanding on how much labeled data is needed to get satisfactory performance. In this paper, we try to address such a question using vehicle license plate character recognition as an example application. We apply computer graphic scripts and Generative Adversarial Networks to generate and augment a large number of annotated, synthesized license plate images with realistic colors, fonts, and character composition from a small number of real, manually labeled license plate images. Generated and augmented data are mixed and used as training data for the license plate recognition network modified from DenseNet. The experimental results show that the model trained from the generated mixed training data has good generalization ability, and the proposed approach achieves a new state-of-the-art accuracy on Dataset-1 and AOLP, even with a very limited number of original real license plates. In addition, the accuracy improvement caused by data generation becomes more significant when the number of labeled images is reduced. Data augmentation also plays a more significant role when the number of labeled images is increased.
We show that every n-vertex cubic graph with girth at least g have domination number at most 0.299871n+O(n/g)<3n/10+O(n/g).
We give an effective version of a result reported by Serre asserting that the images of the Galois representations attached to an abelian surface with $\End(A)= \mathbb{Z}$ are as large as possible for almost every prime. Our algorithm depends on the truth of Serre's conjecture for two dimensional odd irreducible Galois representations. Assuming this conjecture we determine the finite set of primes with exceptional image.
A family of triaxial St\"ackel potential-density pairs is introduced. With the help of a Quadratic Programming method, a linear combination of potential-density pairs of this family which fits a given projected density distribution can be built. This deprojection strategy can be used to model the potentials of triaxial elliptical galaxies with or without dark halos. Besides, we show that the expressions for the St\"ackel triaxial density and potential are considerably simplified when expressed in terms of divided differences, which are convenient numerically. We present an example of triaxial deprojection for the galaxy NGC~5128 whose photometry follows the de Vaucouleurs law.
We propose a new method to understand quantum entanglement using the thermo field dynamics (TFD) described by a double Hilbert space. The entanglement states show a quantum-mechanically complicated behavior. Our new method using TFD makes it easy to understand the entanglement states, because the states in the tilde space in TFD play a role of tracer of the initial states. For our new treatment, we define an extended density matrix on the double Hilbert space. From this study, we make a general formulation of this extended density matrix and examine some simple cases using this formulation. Consequently, we have found that we can distinguish intrinsic quantum entanglement from the thermal fluctuations included in the definition of the ordinary quantum entanglement at finite temperatures. Through the above examination, our method using TFD can be applied not only to equilibrium states but also to non-equilibrium states. This is shown using some simple finite systems in the present paper.
We investigate the deformations of pairs $(X,L)$, where $L$ is a line bundle on a smooth projective variety $X$, defined over an algebraically closed field $\mathbb{K}$ of characteristic 0. In particular, we prove that the DG-Lie algebra controlling the deformations of the pair $(X,L)$ is homotopy abelian whenever $X$ has trivial canonical bundle, and so these deformations are unobstructed.
Recently, in their attempt to construct steady state thermodynamics (SST), Komatsu, Nakagwa, Sasa, and Tasaki found an extension of the Clausius relation to nonequilibrium steady states in classical stochastic processes. Here we derive a quantum mechanical version of the extended Clausius relation. We consider a small system of interest attached to large systems which play the role of heat baths. By only using the genuine quantum dynamics, we realize a heat conducting nonequilibrium steady state in the small system. We study the response of the steady state when the parameters of the system are changed abruptly, and show that the extended Clausius relation, in which "heat" is replaced by the "excess heat", is valid when the temperature difference is small. Moreover we show that the entropy that appears in the relation is similar to von Neumann entropy but has an extra symmetrization with respect to time-reversal. We believe that the present work opens a new possibility in the study of nonequilibrium phenomena in quantum systems, and also confirms the robustness of the approach by Komtatsu et al.
We present an existence result for L\'evy-type processes which requires only weak regularity assumptions on the symbol $q(x,\xi)$ with respect to the space variable $x$. Applications range from existence and uniqueness results for L\'evy-driven SDEs with H\"older continuous coefficients to existence results for stable-like processes and L\'evy-type processes with symbols of variable order. Moreover, we obtain heat kernel estimates for a class of L\'evy and L\'evy-type processes. The paper includes an extensive list of L\'evy(-type) processes satisfying the assumptions of our results.
The minimal flavor structures for both quarks and leptons are proposed to address fermion mass hierarchy and flavor mixings by bi-unitary decomposition of the fermion mass matrix. The real matrix ${\bf M}_0^f$ is completely responsive to family mass hierarchy, which is expressed by a close-to-flat matrix structure. The left-handed unitary phase ${\bf F}_L^f$ provides the origin of CP violation in quark and lepton mixings, which can be explained as a quantum effect between Yukawa interaction states and weak gauge states. The minimal flavor structure is realized by just 10 parameters without any redundancy, corresponding to 6 fermion masses, 3 mixing angles and 1 CP violation in the quark/lepton sector. This approach provides a general flavor structure independent of the specific quark or lepton flavor data. We verify the validation of the flavor structure by reproducing quark/lepton masses and mixings. Some possible scenarios that yield the flavor structure are also discussed.
We have derived fourth-order perturbative equations in Lagrangian perturbation theory for a cosmological dust fluid. These equations are derived under the supposition of Newtonian cosmology in the Friedmann-Lema\^{i}tre-Robertson-Walker Universe model. Even if we consider the longitudinal mode in the first-order perturbation, the transverse mode appears in the third-order perturbation. Furthermore, in this case, six longitudinal-mode equations and four transverse-mode equations appear in the fourth-order perturbation. The application of the fourth-order perturbation leads to a precise prediction of the large-scale structure.
I discuss a few of the recent developments in nuclear reactions at very low energies with emphasis on the role of radioactive beam facilities.
Porous carbons are used in a wide range of applications, including electrochemical double layer capacitors for energy storage, in which electrolyte ion properties under confinement are crucial for the performance of the systems. While many synthesis techniques lead to the presence of surface functional groups, their effect on the adsorption and diffusion of electrolyte ions is still poorly understood. In this study we investigate the effect of surface chemistry on dynamical and structural properties of adsorbed ions through molecular dynamics simulations of a neat ionic liquid in contact with several zeolite templated carbons. The steric and specific influence of functional groups is explored using three structures: a structure without any functional groups; a structure with ester, hydroxyl, anhydride acid and carboxyl functional groups; and a structure where the oxygen and hydrogen atoms are replaced by carbon atoms. We show that the functionalization has a limited impact on the structure of the confined electrolyte but affects the diffusion coefficients, and that the relative importance of the structure and chemical nature of the functional groups is not the same depending on the ion type and property considered.
Chameleon theories of gravity predict that the gaseous component of isolated dwarf galaxies rotates with a faster velocity than the stellar component. In this paper, we exploit this effect to obtain new constraints on the model parameters using the measured rotation curves of six low surface brightness galaxies. For $f(R)$ theories, we rule out values of $f_{R0}>10^{-6}$. For more general theories, we find that the constraints from Cepheid variable stars are currently more competitive than the bounds we obtain here but we are able to rule out self-screening parameters $\chi_c>10^{-6}$ for fifth-force strengths (coupling of the scalar to matter) as low as $0.05$ the Newtonian force. This region of parameter space has hitherto been inaccessible to astrophysical probes. We discuss the future prospects for improving these bounds.
This note is concerned with a modeling question arising from the mean field games theory. We show how to model mean field games involving a major player which has a strategic advantage, while only allowing closed loop markovian strategies for all the players. We illustrate this property through three examples.
We present preliminary reconstructions of the EUV from 26 to 34\,nm from February 1997 to May 2005, covering most of solar cycle 23. The reconstruction is based on synthetic EUV spectra calculated with the spectral synthesis code Solar Modeling in 3D (SolMod3D). These spectra are weighted by the relative area coverage of the coronal features as identified from EIT images. The calculations are based on one-dimensional atmospheric structures that represent a temporal and spatial mean of the chromosphere, transition region, and corona. The employed segmentation analysis considers coronal holes, the quiet corona, and active regions identified on the solar disk. The reconstructed EUV irradiance shows a good agreement with observations taken with the CELIAS/SEM instrument onboard SOHO. Further improvement of the reconstruction including more solar features as well as the off-limb detection of activity features will be addressed in the near future.
We consider higher dimensional generalizations of the four dimensional topological Taub-NUT-AdS solutions, where the angular spheres are replaced by planes and hyperboloids. The thermodynamics of these configurations is discussed to some extent. The results we find suggest that the entropy/area relation is always violated in the presence of a NUT charge. We argue also that the conjectured AdS/CFT correspondence may teach us something about the physics in spacetimes containing closed timelike curves. To this aim, we use the observation that the boundary metric of a (D+1)-dimensional Taub-NUT-AdS solution provides a D-dimensional generalization of the known G\"odel-type spacetimes.
Using gyroscopes we generalize results, obtained for the gravitomagnetic clock effect in the particular case when the exterior spacetime is produced by a rotating dust cylinder, to the case when the vacuum spacetime is described by the general cylindrically symmetric Lewis spacetime. Results are contrasted with those obtained for the Kerr spacetime.
We present 230 GHz Submillimeter Array continuum and molecular line observations of the newly discovered FUor candidate HBC722. We report the detection of seven 1.3 mm continuum sources in the vicinity of HBC722, none of which correspond to HBC722 itself. We compile infrared and submillimeter continuum photometry of each source from previous studies and conclude that three are Class 0 embedded protostars, one is a Class I embedded protostar, one is a Class I/II transition object, and two are either starless cores or very young, very low luminosity protostars or first hydrostatic cores. We detect a northwest-southeast outflow, consistent with the previous detection of such an outflow in low-resolution, single-dish observations, and note that its axis may be precessing. We show that this outflow is centered on and driven by one of the nearby Class 0 sources rather than HBC722, and find no conclusive evidence that HBC722 itself is driving an outflow. The non-detection of HBC722 in the 1.3 mm continuum observations suggests an upper limit of 0.02 solar masses for the mass of the circumstellar disk. This limit is consistent with typical T Tauri disks and with a disk that provides sufficient mass to power the burst.
Critical temperature regions for resistive switching were found based on HfAlO resistive switching memory. From 5 K to 300 K, the resistive switching appears at 60 K, and then a reversible bipolar switching between the two states is observed at above 150 K. It is suggested that the resistive switching characteristics of the binary transitional metal oxides are governed by thermal assisted percolating conductive paths. The process of charge trap/de-trapping under the external electrical field plays a dominated role with the assumption of the same Joule heating generated by internal conductive filament at different temperatures.