ShantanuT01/DACTYL-Pretraining huggingface dataset:
A process, involving the 7Be core excitation in the Coulomb breakup of 8B into p + 7Be has been investigated. From the experimental results recently obtained in RIKEN we have derived the mixing amplitude of the   | 7Be(1/2-) X (1p_{3/2}); 2+> configuration in the ground state of 8B. Implications on the evaluation of the S17 at stellar energies are discussed.
We discuss an extension of higher order topological phases to include bosonic systems. We present two spin models for a second-order topological phase protected by a global $\mathbb{Z}_2\times\mathbb{Z}_2$ symmetry. One model is built from layers of an exactly solvable cluster model for a one-dimensional $\mathbb{Z}_2\times\mathbb{Z}_2$ topological phase, while the other is built from more conventional spin-couplings (XY or Heisenberg). These models host gapped, but topological, edges, and protected corner modes that fall into a projective representation of the symmetry. Using Jordan-Wigner transformations we show that our models are both related to a bilayer of free Majorana fermions that form a fermionic second-order topological phase. We also discuss how our models can be extended to three-dimensions to form a third-order topological phase.
The recent speculation of Maggiore that the periodicity of a black hole may be the origin of the area quantization law is confirmed. We exclusively utilize the period of motion of an outgoing wave, which is shown to be related to the vibrational frequency of the perturbed black hole, to quantize the horizon areas of a Schwarzschild black hole and a Kerr black hole. It is shown that the equally spaced area spectrum for both cases takes the same form and the spacing is the same as that obtained through the quasinormal mode frequencies. Particularly, for a Kerr black hole, the small angular momentum assumption, which is necessary from the perspective of quasinormal mode, is not employed as the general area spacing is reproduced.
We give results for the distribution and number of flux vacua of various types, supersymmetric and nonsupersymmetric, in IIb string theory compactified on Calabi-Yau manifolds. We compare this with related problems such as counting attractor points.
This paper reports on 3D numerical simulations of dynamics and thermodynamics in the diffuse ISM. Our models are local, account for sheared galactic rotation, magnetic fields, and realistic cooling, and resolve scales ~1-200 pc. This combination permits the study of quasi-steady turbulence in a cloudy medium representing the warm/cold atomic ISM. Turbulence is driven by the magnetorotational instability (MRI); our models are the first to study the saturated state of MRI under strongly inhomogeneous conditions, with cloud/intercloud contrasts of about 100. For volume-averaged densities n=0.25 - 4 cm^3, the saturated-state velocity dispersion ranges from 8-1 km/s, scaling as n^-0.77. The MRI is therefore likely quite important in driving turbulence in low-density ISM regions, both at high latitudes in the inner Galaxy,and throughout the far outer Galaxy. The MRI may be key to suppressing star formation at large radii in spiral galaxies, where without MRI-driven turbulence, a thin, cold layer could form and become gravitationally instable. Our presentation also includes analysis of thermal structure (temperature and density PDFs are broadened and include extreme departures from equilibrium, but retain the classical two-phase bimodal character); results on the distribution of clump masses (the mass spectrum peaks at about 100 solar masses); comparisons of saturated-state MRI scalings with single-phase simulation results (we find B^2 is independent of n); and examples of synthetic HI line profile maps (showing that physical clumps are not easily distinguished in velocity components, and vice versa).
In this paper we consider suitable families of power series distributed random variables, and we study their asymptotic behavior in the fashion of large (and moderate) deviations. We also present two examples of fractional counting processes, where the normalizations of the involved power series distributions can be expressed in terms of the Prabhakar function. The first example allows to consider the counting process in \cite{PoganyTomovski}, the second one is inspired by a model studied in \cite{GarraOrsingherPolito}.
In this review, recent progress in theoretical models for blazar emission will be summarized. The salient features of both leptonic and lepto-hadronic approaches to modeling blazar spectral energy distributions will be reviewed. I will present sample modeling results of spectral energy distributions (SEDs) of different types of blazars along the blazar sequence, including Fermi high-energy gamma-ray data, using both types of models. Special emphasis will be placed on the implications of the recent very-high-energy (VHE) gamma-ray detections of non-traditional VHE gamma-ray blazars, including intermediate and low-frequency-peaked BL Lac objects and even flat-spectrum radio quasars. Due to the featureless optical spectra of BL Lac objects, the redshifts of several BL Lacs remain unknown. I will briefly discuss possible constraints on their redshift using spectral modeling of their SED including Fermi + ground-based VHE gamma-ray data. It will be shown that in some cases, spectral modeling with time-independent single-zone models alone is not sufficient to constrain models, as both leptonic and lepto-hadronic models are able to provide acceptable fits to the overall SED. Subsequently, recent developments of time-dependent and inhomogeneous blazar models will be discussed, including detailed numerical simulations as well as a semi-analytical approach to the time-dependent radiation signatures of shock-in-jet models.
In this paper we answer a question raised in [25], Sec. 4, by showing that the genus zero moduli operad $\{\bar{M}_{0,n+1}\}$ can be endowed with natural descent data that allow it to be considered as the lift to ${\rm Spec}\,\Z$ of an operad over $\F_1$. The relevant descent data are based on a notion of constructible sets and constructible functions over $\F_1$, which describes suitable differences of torifications with a positivity condition on the class in the Grothendieck ring. More generally, we do the same for the operads $\{T_{d,n+1}\}$ (whose components were) introduced in [5]. Finally, we describe a blueprint structure on $\{\bar{M}_{0,n}\}$ and we discuss from this perspective the genus zero boundary modular operad $\{\bar{M}_{g,n+1}^0\}$.
We investigate the impact of the existence of a primordial magnetic field on the filter mass, characterizing the minimum baryonic mass that can form in dark matter (DM) haloes. For masses below the filter mass, the baryon content of DM haloes are severely depressed. The filter mass is the mass when the baryon to DM mass ratio in a halo is equal to half the baryon to DM ratio of the Universe. The filter mass has previously been used in semianalytic calculations of galaxy formation, without taking into account the possible existence of a primordial magnetic field. We examine here its effect on the filter mass. For homogeneous comoving primordial magnetic fields of $B_0 \sim 1$ or 2 nG and a reionization epoch that starts at a redshift $z_s=11$ and is completed at $z_r=8$, the filter mass is increased at redshift 8, for example, by factors 4.1 and 19.8, respectively. The dependence of the filter mass on the parameters describing the reionization epoch is investigated. Our results are particularly important for the formation of low mass galaxies in the presence of a homogeneous primordial magnetic field. For example, for $B_0\sim 1\nG$ and a reionization epoch of $z_s\sim 11$ and $z_r\sim7$, our results indicate that galaxies of total mass $M\sim5 \times 10^8\msun$ need to form at redshifts $z_F\gtrsim 2.0$, and galaxies of total mass $M\sim10^8\msun$ at redshifts $z_F\gtrsim 7.7$.
The iris is considered as the biometric trait with the highest unique probability. The iris location is an important task for biometrics systems, affecting directly the results obtained in specific applications such as iris recognition, spoofing and contact lenses detection, among others. This work defines the iris location problem as the delimitation of the smallest squared window that encompasses the iris region. In order to build a benchmark for iris location we annotate (iris squared bounding boxes) four databases from different biometric applications and make them publicly available to the community. Besides these 4 annotated databases, we include 2 others from the literature. We perform experiments on these six databases, five obtained with near infra-red sensors and one with visible light sensor. We compare the classical and outstanding Daugman iris location approach with two window based detectors: 1) a sliding window detector based on features from Histogram of Oriented Gradients (HOG) and a linear Support Vector Machines (SVM) classifier; 2) a deep learning based detector fine-tuned from YOLO object detector. Experimental results showed that the deep learning based detector outperforms the other ones in terms of accuracy and runtime (GPUs version) and should be chosen whenever possible.
We report the discovery of a stellar over-density 8$^{\circ}$ north of the center of the Small Magellanic Cloud (Small Magellanic Cloud Northern Over-Density; SMCNOD) using data from the first two years of the Dark Energy Survey (DES) and the first year of the MAGellanic SatelLITEs Survey (MagLiteS). The SMCNOD is indistinguishable in age, metallicity and distance from the nearby SMC stars, being primarly composed of intermediate-age stars (6 Gyr, Z=0.001), with a small fraction of young stars (1 Gyr, Z=0.01). The SMCNOD has an elongated shape with an ellipticity of 0.6 and a size of $\sim$ 6x2 deg. It has an absolute magnitude of $M_V \cong$ -7.7, $r_h = 2.1$ kpc, and $\mu_V(r<r_h)$ = 31.2 mag arcsec$^{-2}$. We estimate a stellar mass of $\sim 10^5$ $M_{\odot}$, following a Kroupa mass function. The SMCNOD was probably removed from the SMC disk by tidal stripping, since it is located near the head of the Magellanic Stream, and the literature indicates likely recent LMC-SMC encounters. This scenario is supported by the lack of significant HI gas. Other potential scenarios for the SMCNOD origin are a transient over-density within the SMC tidal radius or a primordial SMC satellite in advanced stage of disruption.
Collective excitations spectrum of Dirac electrons in mono and bilayer graphene in the presence of a uniform magnetic field is investigated. Analytical results for inter-Landau band plasmon spectrum within the self-consistent-field approach are obtained. SdH type oscillations that are a monotonic function of the magnetic field are observed in the plasmon spectrum of both mono- and bi-layer graphene systems. The results presented are also compared with those obtained in conventional 2DEG. The chiral nature of the quasiparticles in mono and bilayer graphene system results in the observation of $\pi$ and $2\pi$ Berry's phase in the SdH- type oscillations in the plasmon spectrum.
A logarithmic oscillator (in short, log-oscillator) behaves like an ideal thermostat because of its infinite heat capacity: when it weakly couples to another system, time averages of the system observables agree with ensemble averages from a Gibbs distribution with a temperature T that is given by the strength of the logarithmic potential. The resulting equations of motion are Hamiltonian and may be implemented not only in a computer but also with real-world experiments, e.g., with cold atoms.
Several types of binary systems have been detected up to now at high and very high gamma-ray energies, including microquasars, young pulsars around massive stars and colliding wind binaries. The study of the sources already known, and of the new types of sources expected to be discovered with the unprecedented sensitivity of CTA, will allow us to qualitatively improve our knowledge on particle acceleration, emission and radiation reprocessing, and on the dynamics of flows and their magnetic fields. Here we present some examples of the capabilities of CTA to probe the flux and spectral changes that typically occur in these astrophysical sources, as well as to search for delays in correlated X-ray/TeV variability with CTA and satellites of the CTA era. Our results show that our knowledge of the high-energy physics in binary systems will significantly deepen with CTA.
We calculate the cross sections for the $p(p,n\pi^{+})p$ and $p(p,p\pi^{0})p$ reactions for proton beam energies near threshold in a covariant one-boson-exchange model, which incorporates the exchange of $\pi$, $\rho$, $\sigma$ and $\omega$ mesons and treats both nucleon and delta isobar as intermediate states. The final state interaction effects have also been included. The $\omega$ meson exchange is found to contribute significantly at these energies, which, along with other meson exchanges, provides an excellent agreement with the data. The cross sections at beam energies $\leq$ 300 MeV are almost free from the contributions of the $\Delta$ isobar excitation.
We investigate large time existence of solutions of the Navier-Stokes-Boussinesq equations with spatially almost periodic large data when the density stratification is sufficiently large. In 1996, Kimura and Herring \cite{KH} examined numerical simulations to show a stabilizing effect due to the stratification. They observed scattered two-dimensional pancake-shaped vortex patches lying almost in the horizontal plane. Our result is a mathematical justification of the presence of such two-dimensional pancakes. To show the existence of solutions for large times, we use $\ell^1$-norm of amplitudes. Existence for large times is then proven using techniques of fast singular oscillating limits and bootstrapping argument from a global-in-time unique solution of the system of limit equations.
Particle acceleration mechanisms in supermassive black hole jets, such as shock acceleration, magnetic reconnection, and turbulence, are expected to have observable signatures in the multi-wavelength polarization properties of blazars. The recent launch of the Imaging X-ray Polarimetry Explorer (IXPE) enables us, for the first time, to use polarization in the X-ray band (2-8 keV) to probe the properties of the jet synchrotron emission in high-frequency-peaked BL Lac objects (HSPs). We report the discovery of X-ray linear polarization (degree $\Pi_{\rm x}=15\pm$2\% and electric-vector position angle $\Psi_{\rm x}=35^\circ\pm4^\circ$) from the jet of the HSP Mrk~421 in an average X-ray flux state. At the same time, the degree of polarization at optical, infrared, and millimeter wavelengths was found to be lower by at least a factor of 3. During the IXPE pointing, the X-ray flux of the source increased by a factor of 2.2, while the polarization behavior was consistent with no variability. The higher level of $\Pi_{\rm x}$ compared to longer wavelengths, and the absence of significant polarization variability, suggest a shock as the most likely X-ray emission site in the jet of Mrk 421 during the observation. The multiwavelength polarization properties are consistent with an energy-stratified electron population, where the particles emitting at longer wavelengths are located farther from the acceleration site, where they experience a more disordered magnetic field.
In recent times, the availability of inexpensive image capturing devices such as smartphones/tablets has led to an exponential increase in the number of images/videos captured. However, sometimes the amateur photographer is hindered by fences in the scene which have to be removed after the image has been captured. Conventional approaches to image de-fencing suffer from inaccurate and non-robust fence detection apart from being limited to processing images of only static occluded scenes. In this paper, we propose a semi-automated de-fencing algorithm using a video of the dynamic scene. We use convolutional neural networks for detecting fence pixels. We provide qualitative as well as quantitative comparison results with existing lattice detection algorithms on the existing PSU NRT data set and a proposed challenging fenced image dataset. The inverse problem of fence removal is solved using split Bregman technique assuming total variation of the de-fenced image as the regularization constraint.
Why are different mass states coherent? What is the correct formula for the oscillation phase? How can textbook formulas for oscillations in time describe experiments which never measure time? How can we treat the different velocities and different transit times of different mass eigenstates and avoid incorrect factors of two? How can textbook forumulas which describe coherence between energy states be justified when Stodolsky's theorem states there is no coherence between different energies? Is covariant relativistic quantum field theory necessary to describe neutrino oscillations? How important is the detector, which is at rest in the laboratory and cannot be Lorentz tranformed to other frames?   These questions are answered by a simple rigorous calculation which includes the quantum fluctuations in the position of the detector and in the transit time between source and detector. The commonly used standard formula for neutrino oscillation phases is confirmed. An "ideal" detector which measures precisely the energy and momentum of the neutrino destroys all phases in the initial wave packet and cannot observe oscillations. A realistic detector preserves the phase differences between neutrinos having the same energy and different momenta and confirms the standard formula. Whether phase differences between neutrinos with different energies are observable or destroyed by the detector is irrelevant.
Contour detection has been a fundamental component in many image segmentation and object detection systems. Most previous work utilizes low-level features such as texture or saliency to detect contours and then use them as cues for a higher-level task such as object detection. However, we claim that recognizing objects and predicting contours are two mutually related tasks. Contrary to traditional approaches, we show that we can invert the commonly established pipeline: instead of detecting contours with low-level cues for a higher-level recognition task, we exploit object-related features as high-level cues for contour detection.   We achieve this goal by means of a multi-scale deep network that consists of five convolutional layers and a bifurcated fully-connected sub-network. The section from the input layer to the fifth convolutional layer is fixed and directly lifted from a pre-trained network optimized over a large-scale object classification task. This section of the network is applied to four different scales of the image input. These four parallel and identical streams are then attached to a bifurcated sub-network consisting of two independently-trained branches. One branch learns to predict the contour likelihood (with a classification objective) whereas the other branch is trained to learn the fraction of human labelers agreeing about the contour presence at a given point (with a regression criterion).   We show that without any feature engineering our multi-scale deep learning approach achieves state-of-the-art results in contour detection.
The energy eigenvalues and the wave functions of an $\alpha$ particle in a Bohrium $270$ nucleus were calculated by solving Schr\"odinger equation for Generalized Symmetric Woods-Saxon potential. Using the energy spectrum by excluding and including the quasi-bound eigenvalues, entropy, internal energy, Helmholtz energy, and specific heat, as functions of reduced temperature were calculated. Stability and emission characteristics are interpreted in terms of the wave and thermodynamic functions. The kinetic energy of a decayed $\alpha$ particle was calculated using the quasi-bound states, which is found close to the experimental value.
A strong photon-photon nonlinear interaction is a necessary condition for photon blockade. Moreover, this nonlinearity can also result a bistable behavior in the cavity field. We analyze the relation between detecting field and photon blockade in a superconducting circuit QED system, and show that photon blockade cannot occur when the detecting field is in the bistable regime. This photon blockade is the microwave-photonics analog of the Coulomb blockade. We further demonstrate that the photon transmission through such system can be controlled (from photon blockade to transparency) by the detecting field. Numerical calculations show that our proposal is experimentally realizable with current technology.
In this paper, we introduce a class of stochastic partial differential equations (SPDEs) with fractional time-derivatives, and study the $L_2$-theory of the equations. This class of SPDEs can be used to describe random effects on transport of particles in medium with thermal memory or particles subject to sticking and trapping.
Regular observations by the All Sky Monitor aboard the Rossi X-ray Timing Explorer satellite have yielded well-sampled light-curves with a time baseline of over ten years. We find that up to eight of the sixteen brightest persistent low mass X-ray binaries show significant, possible sinusoidal, variations with periods of order ten years. We speculate on its possible origin and prevalence in the population of low mass X-ray binaries and we find the presence of a third object in the system, or long-period variability intrinsic to the donor star, as being attractive origins for the X-ray flux modulation we detect. For some of the objects in which we do not detect a signal, there is substantial short-term variation which may hide modest modulation on long time-scales. Decade time-scale modulations may thus be even more common.
We derive an analytical lower bound for the concurrence of tripartite quantum mixed states. A functional relation is established relating concurrence and the generalized partial transpositions.
Let $f(q)$ denote Ramanujan's mock theta function \[f(q) = \sum_{n=0}^{\infty} a(n) q^{n} := 1+\sum_{n=1}^{\infty} \frac{q^{n^{2}}}{(1+q)^{2}(1+q^{2})^{2}\cdots(1+q^{n})^{2}}.\] It is known that there are many linear congruences for the coefficients of $f(q)$ and other mock theta functions. We prove that if the linear congruence $a(mn+t) \equiv 0 \pmod{\ell}$ holds for some prime $\ell \geq 5$, then $\ell | m$ and $(\frac{24t-1}{\ell}) \neq (\frac{-1}{\ell})$. We prove analogous results for the mock theta function $\omega(q)$ and for a large class of weakly holomorphic modular forms which includes $\eta$-quotients. This extends work of Radu in which he proves a conjecture of Ahlgren and Ono for the partition function $p(n)$.
We remark on the Garnier system in two variables.
The temperature ($T$) dependent metal-insulator transition (MIT) in VO$_2$ is investigated using bulk sensitive hard x-ray ($\sim$ 8 keV) valence band, core level, and V 2$p-3d$ resonant photoemission spectroscopy (PES). The valence band and core level spectra are compared with full-multiplet cluster model calculations including a coherent screening channel. Across the MIT, V 3$d$ spectral weight transfer from the coherent ($d^1\underbar{\it {C}}$ final) states at Fermi level to the incoherent ($d^{0}+d^1\underbar{\it {L}}$ final) states, corresponding to the lower Hubbard band, lead to gap-formation. The spectral shape changes in V 1$s$ and V 2$p$ core levels as well as the valence band are nicely reproduced from a cluster model calculations, providing electronic structure parameters. Resonant-PES finds that the $d^1\underbar{\it{L}}$ states resonate across the V 2$p-3d$ threshold in addition to the $d^{0}$ and $d^1\underbar{\it {C}}$ states. The results support a Mott-Hubbard transition picture for the first order MIT in VO$_2$.