ShantanuT01/DACTYL-Pretraining huggingface dataset:
Using the Wind/WAVES radio observations from 2010-2013, we present an analysis of the 123 decametric-hectometric (DH) type II solar radio bursts during this period, the associated type III burst properties, and their correlation with solar energetic proton (SEP) properties determined from analysis of the Geostationary Operational Environmental Satellite (GOES) observations. We present a useful catalog of the type II burst, type III burst, Langmuir wave, and proton flux properties for these 123 events, which we employ to develop a statistical relationship between the radio properties and peak proton flux that can be used to forecast SEP events. We find that all SEP events with a peak > 10 MeV flux above 15 pfu are associated with a type II burst and virtually all SEP events, 92%, are also associated with a type III radio burst. Based on a principal component analysis, the radio burst properties that are most highly correlated with the occurrence of gradual SEP events and account for the most variance in the radio properties are the type III burst intensity and duration. Further, a logistic regression analysis with the radio-derived principal component (dominated by the type III and type II radio burst intensity and type III duration) obtains SEP predictions approaching the human forecaster rates, with a false alarm rate of 22%, a probability of detection of 62%, and with 85% of the classifications correct. Therefore, type III radio bursts that occur along with a DH type II burst are shown to be an important diagnostic that can be used to forecast SEP events.
We calculate the asymmetries for the processes $\vec\gamma+\vec p\to \Lambda_c^+ (\Sigma_c^+)+\bar{D^0}$ and $\vec\gamma+\vec p\to \Lambda_c^+ (\Sigma_c^+)+\bar{D^*}$, induced by circularly polarized photons on a polarized proton target in the framework of an effective Lagrangian model. We found large and positive values for the asymmetry induced by the $z-$component of the proton polarization, in a wide energy region, from threshold up to $E_\gamma=70$ GeV. In the case of pseudoscalar meson photoproduction, the predictions are qualitatively model-independent. For $D^*$-photoproduction, there is a strong dependence of the asymmetries on $N\Lambda_c D(D^*)$-coupling constants.
Using the Millennium N-body simulation we explore how the shape and angular momentum of galaxy dark matter haloes surrounding the largest cosmological voids are oriented. We find that the major and intermediate axes of the haloes tend to lie parallel to the surface of the voids, whereas the minor axis points preferentially in the radial direction. We have quantified the strength of these alignments at different radial distances from the void centres. The effect of these orientations is still detected at distances as large as 2.2 R_void from the void centre. Taking a subsample of haloes expected to contain disc-dominated galaxies at their centres we detect, at the 99.9% confidence level, a signal that the angular momentum of those haloes tends to lie parallel to the surface of the voids. Contrary to the alignments of the inertia axes, this signal is only detected in shells at the void surface (1<R<1.07 R_void) and disappears at larger distances. This signal, together with the similar alignment observed using real spiral galaxies (Trujillo, Carretero & Patiri 2006), strongly supports the prediction of the Tidal Torque theory that both dark matter haloes and baryonic matter have acquired, conjointly, their angular momentum before the moment of turnaround.
We present the results for the low energy properties of the infinite dimensional t-J model with $J=0$, using $O(\lambda^2)$ equations of the extremely correlated Fermi liquid formalism. The parameter $\lambda \in [0,1]$ is analogous to the inverse spin parameter $1/(2S)$ in quantum magnets. The present analytical scheme allows us to approach the physically most interesting regime near the Mott insulating state $n\lesssim 1$. It overcomes the limitation to low densities $n \lesssim .7$ of earlier calculations, by employing a variant of the skeleton graph expansion, and a high frequency cutoff that is essential for maintaining the known high-T entropy. The resulting quasiparticle weight $Z$, the low $\omega,T $ self energy and the resistivity are reported. These are quite close at all densities to the exact numerical results of the $U=\infty$ Hubbard model, obtained using the dynamical mean field theory. The present calculation offers the advantage of generalizing to finite $T$ rather easily, and allows the visualization of the loss of coherence of Fermi liquid quasiparticles by raising $T$. The present scheme is generalizable to finite dimensions and a non vanishing $J$.
The phase transitions in the transverse field Ising model in a competing spatially modulated (periodic and oscillatory) longitudinal field are studied numerically. There is a multiphase point in absence of the transverse field where the degeneracy for a longitudinal field of wavelength $\lambda$ is $(\frac {1 + \sqrt{5}}{2})^{2N/\lambda}$ for a system with $N$ spins, an exact result obtained from the known result for $\lambda =2$. The phase transitions in the $\Gamma $ (transverse field) versus $h_0$ (amplitude of the longitudinal field) phase diagram are obtained from the vanishing of the mass gap $\Delta$. We find that for all the phase transition points obtained in this way, $\Delta $ shows finite size scaling behaviour signifying a continuous phase transition everywhere. The values of the critical exponents show that the model belongs to the universality class of the two dimensional Ising model. The longitudinal field is found to have the same scaling behaviour as that of the transverse field, which seems to be a unique feature for the competing field. The phase boundaries for two different wavelengths of the modulated field are obtained. Close to the multiphase point at $h_c$, the phase boundary behaves as $(h_c - h_0)^b$, where $b$ is also $\lambda$ dependent.
In this paper, we construct a bound copula, which can reach both Frechet's lower and upper bounds for perfect positive and negative dependence cases. Since it covers a wide range of dependency and simple for computational purposes, it can be very useful. We then develop a new perturbed copula using the lower and upper bounds of Frechet copula and show that it satisfies all properties of a copula. In some cases, it is very difficult to get results such as distribution functions and the expected values in explicit form by using copulas such as Archemedes, Guassian, $t$-copula. Thus, we can use these new copulas. For both copulas, we derive the strength of measures of the dependency such as Spearman's rho, Kendall's tau, Blomqvist's beta and Gini's gamma, and the coefficients of the tail dependency. As an application, we use the bound copula to analyze the dependency between two service times to evaluate the mean waiting time and the mean service time when customers launch two replicas of each task on two parallel servers using the cancel-on-finish policy. We assume that the inter-arrival time is exponential and the service time is general.
It is shown that the presence of the Majorana fermion edge states along the perimeter of a topological superconductor can be probed using an interacting quantum dot coupled to three terminals: two spin-polarized (ferromagnetic) leads and one lead supporting the Majorana edge states. The hybridization with the Majorana states induces a particular type of the Kondo effect with non-Fermi-liquid properties which can be detected by performing linear conductance measurements between the source and drain normal leads: the temperature dependence of the conductance is characteristically different from that in the conventional Kondo effect.
The free-streaming of keV-scale particles impacts structure growth on scales that are probed by the Lyman-alpha forest of distant quasars. Using an unprecedentedly large sample of medium-resolution QSO spectra from the ninth data release of SDSS, along with a state-of-the-art set of hydrodynamical simulations to model the Lyman-alpha forest in the non-linear regime, we issue one of the tightest bounds to date, from Ly-$\alpha$ data alone, on pure dark matter particles : $m_X > 4.09 \: \rm{keV}$ (95% CL) for early decoupled thermal relics such as a hypothetical gravitino, and correspondingly $m_s > 24.4 \: \rm{keV}$ (95% CL) for a non-resonantly produced right-handed neutrino. This limit depends on the value on $n_s$, and Planck measures a higher value of $n_s$ than SDSS-III/BOSS. Our bounds thus change slightly when Ly-$\alpha$ data are combined with CMB data from Planck 2016. The limits shift to $m_X > 2.96 \: \rm{keV}$ (95% CL) and $m_s > 16.0 \: \rm{keV}$ (95% CL). Thanks to SDSS-III data featuring smaller uncertainties and covering a larger redshift range than SDSS-I data, our bounds confirm the most stringent results established by previous works and are further at odds with a purely non-resonantly produced sterile neutrino as dark matter.
In the context of AGN unification scheme rapid variability properties play an important role in understanding any intrinsic differences between sources in different classes. In this respect any clue based on spectral properties will be very useful toward understanding the mechanisms responsible for the origin of rapid small scale optical variations, or microvariability. Here we have added spectra of 46 radio-quiet quasars (RQQSOs) and Seyfert 1 galaxies to those of our previous sample of 37 such objects, all of which had been previously searched for microvariability. We took new optical spectra of 33 objects and obtained 13 others from the literature. Their \hbeta and \mgii emission lines were carefully fit to determine line widths (FWHM) as well as equivalent widths (EW) due to the broad emission line components. The line widths were used to estimate black hole masses and Eddington ratios, $\ell$. Both EW and FWHM are anticorrelated with $\ell$. Nearly all trends were in agreement with our previous work, although the tendency for sources exhibiting microvariability to be of lower luminosity was not confirmed. Most importantly, this whole sample of EW distributions provides no evidence for the hypothesis that a weak jet component in the radio quiet AGNs is responsible for their microvariability.
This paper describes the first catalogue of photometrically-derived stellar mass estimates for intermediate-redshift (z < 0.65) galaxies in the Galaxy And Mass Assembly (GAMA) spectroscopic redshift survey. These masses, as well as the full set of ancillary stellar population parameters, will be made public as part of GAMA data release 2. Although the GAMA database does include NIR photometry, we show that the quality of our stellar population synthesis fits is significantly poorer when these NIR data are included. Further, for a large fraction of galaxies, the stellar population parameters inferred from the optical-plus-NIR photometry are formally inconsistent with those inferred from the optical data alone. This may indicate problems in our stellar population library, or NIR data issues, or both; these issues will be addressed for future versions of the catalogue. For now, we have chosen to base our stellar mass estimates on optical photometry only. In light of our decision to ignore the available NIR data, we examine how well stellar mass can be constrained based on optical data alone. We use generic properties of stellar population synthesis models to demonstrate that restframe colour alone is in principle a very good estimator of stellar mass-to-light ratio, M*/Li. Further, we use the observed relation between restframe (g-i) and M*/Li for real GAMA galaxies to argue that, modulo uncertainties in the stellar evolution models themselves, (g-i) colour can in practice be used to estimate M*/Li to an accuracy of < ~0.1 dex. This 'empirically calibrated' (g-i)-M*/Li relation offers a simple and transparent means for estimating galaxies' stellar masses based on minimal data, and so provides a solid basis for other surveys to compare their results to z < ~0.4 measurements from GAMA.
3D motion estimation including scene flow and point cloud registration has drawn increasing interest. Inspired by 2D flow estimation, recent methods employ deep neural networks to construct the cost volume for estimating accurate 3D flow. However, these methods are limited by the fact that it is difficult to define a search window on point clouds because of the irregular data structure. In this paper, we avoid this irregularity by a simple yet effective method.We decompose the problem into two interlaced stages, where the 3D flows are optimized point-wisely at the first stage and then globally regularized in a recurrent network at the second stage. Therefore, the recurrent network only receives the regular point-wise information as the input. In the experiments, we evaluate the proposed method on both the 3D scene flow estimation and the point cloud registration task. For 3D scene flow estimation, we make comparisons on the widely used FlyingThings3D and KITTIdatasets. For point cloud registration, we follow previous works and evaluate the data pairs with large pose and partially overlapping from ModelNet40. The results show that our method outperforms the previous method and achieves a new state-of-the-art performance on both 3D scene flow estimation and point cloud registration, which demonstrates the superiority of the proposed zero-order method on irregular point cloud data.
In this paper, we will discuss the use of a Sampling Method to reconstruct impenetrable inclusions from Electrostatic Cauchy data. We consider the case of a perfectly conducting and impedance inclusion. In either case, we show that the Dirichlet to Neumann mapping can be used to reconstruct impenetrable sub-regions via a sampling method. We also propose a non-iterative method based on boundary integral equations to reconstruct the impedance parameter using the reconstructed boundary of the inclusion from the knowledge of multiple Cauchy pairs which can be computed from Dirichlet to Neumann mapping. Some numerical reconstructions are presented in two space dimensions.
An exactly solvable model is introduced, which is equivalent to the exact shell-model treatment of protons and neutrons in a single j-shell for Fermi-type excitations. Exact energies, quasiparticle numbers and double beta decay Fermi amplitudes are computed and compared with the results of both the standard quasiparticle random phase approximation (QRPA) and the renormalized one (RQRPA), and also with those corresponding to the hamiltonian in the quasiparticle basis (qp). A zero excitation energy state is found in the exact case, occuring at a value of the residual particle-particle interaction at which the QRPA collapse. The RQRPA and the qp solutions do not include this zero-energy eigenvalue in their spectra, probably due to spurious correlations.
We present studies of the cyclotron resonance (CR) in thick Cd$_x$Hg$_{1-x}$Te films with different cadmium concentrations corresponding to inverted and normal band order, as well as to an almost linear energy dispersion. Our results demonstrate that formation of two-dimensional topological surface states requires sharp interfaces between layers with inverted and normal band order, in which case the corresponding CR is clearly observed for the out-of-plane orientation of magnetic field, but does not show up for an in-plane orientation. By contrast, all samples having more conventional technological design with smooth interfaces (i.e., containing regions of Cd$_x$Hg$_{1-x}$Te with gradually changing Cd content $x$) show equally pronounced CR in both in-plane and out-of-plane magnetic field revealing that CR is excited in three-dimensional states. Modeling of the surface states for different film designs supports our main observations. In all samples, we observe additional broad helicity-independent resonances which are attributed to photo-ionization and magnetic freeze-out of impurity states.
We study the inner-structure of a charged black-hole which is formed from the gravitational collapse of a self-gravitating charged scalar-field. Starting with a regular spacetime, we follow the evolution through the formation of an apparent horizon, a Cauchy horizon and a final central singularity. We find a null, weak, mass-inflation singularity along the Cauchy horizon, which is a precursor of a strong, spacelike singularity along the $r=0$ hypersurface.
Faraday tomography of radio polarimetric data below 200 MHz from LOFAR are providing us with a new perspective on the diffuse and magnetized interstellar medium (ISM). Of particular interest is the discovery of Faraday-rotated synchrotron polarization associated with neutral gas, as traced by atomic hydrogen (HI) and dust. Here we present the first in-depth numerical study of these LOFAR results. We produce and analyze comprehensive synthetic observations of low-frequency synchrotron polarization from MHD simulations of colliding super shells in the multiphase ISM. We define five distinct gas phases over more than four orders of magnitude in gas temperature and density, ranging from hot, and warm, fully ionized gas to cold neutral medium. We focus on the contribution of each gas phase to synthetic observations of both rotation measure and synchrotron polarized intensity below 200 MHz. We also investigate the link between the latter and synthetic observations of optically thin HI gas. We find that, not only the fully ionized gas but also the warm partially ionized and neutral phases strongly contribute to the total rotation measure and polarized intensity. However, the contribution of each phase to the observables strongly depends on the choice of integration axis and the orientation of the mean magnetic field with respect to the shell-collision axis. Strong correlation between HI synthetic data and synchrotron polarized intensity, reminiscent of LOFAR results, is obtained with lines of sight perpendicular to the mean magnetic field direction. Our study suggests that multiphase modelling of MHD processes is needed in order to interpret observations of the radio sky at low frequency. This work is a first step toward understanding the complexity of low-frequency synchrotron emission that will be soon revolutionized by large-scale surveys with LOFAR and the SKA.
In this note, we study the infinitesimal forms of Deligne cycle class maps. As an application, we prove that the infinitesimal form of a conjecture by Beilinson is true.
The discovery of graphene some ten years ago was the first proof of a free-standing two-dimensional (2D) solid phase. Here, using quantum molecular dynamics simulations of nanoscale gold patches suspended in graphene pores, we predict the existence of an atomically thin, free-standing 2D liquid phase. The liquid phase, enabled by the exceptional planar stability of gold due to relativistic effects, demonstrates extreme fluxionality of metal nanostructures and opens possibilities for a variety of nanoscale phenomena.
This paper contains a proof of a conjecture of Braverman concerning Laumon quasiflag spaces. We consider the generating function Z(m), whose coefficients are the integrals of the equivariant Chern polynomial (with variable m) of the tangent bundles of the Laumon spaces. We prove Braverman's conjecture, which states that Z(m) coincides with the eigenfunction of the Calogero-Sutherland hamiltonian, up to a simple factor which we specify. This conjecture was inspired by the work of Nekrasov in the affine \hat{sl}_n setting, where a similar conjecture is still open.
The phase transition of hadronic to quark matter and the boundaries of the mixed hadron-quark coexistence phase are studied within the two Equation of State (EoS) model. The relativistic effective mean field approach with constant and density dependent meson-nucleon couplings is used to describe hadronic matter, and the MIT Bag model is adopted to describe quark matter. The boundaries of the mixed phase for different Bag constants are obtained solving the Gibbs equations.   We notice that the dependence on the Bag parameter of the critical temperatures (at zero chemical potential) can be well reproduced by a fermion ultrarelativistic quark gas model, without contribution from the hadron part. At variance the critical chemical potentials (at zero temperature) are very sensitive to the EoS of the hadron sector. Hence the study of the hadronic EoS is much more relevant for the determination of the transition to the quark-gluon-plasma at finite baryon density and low-T. Moreover in the low temperature and finite chemical potential region no solutions of the Gibbs conditions are existing for small Bag constant values, B < (135 MeV)^4. Isospin effects in asymmetric matter appear relevant in the high chemical potential regions at lower temperatures, of interest for the inner core properties of neutron stars and for heavy ion collisions at intermediate energies.
We use a numerical code for accurate computation of the amplitude of linear density perturbations and gravitational waves generated by single-field inflation models to study the accuracy of existing analytic results based on the slow-roll approximation. We use our code to calculate the coefficient of an expansion about the exact analytic result for power-law inflation; this generates a fitting function which can be applied to all inflationary models to obtain extremely accurate results. In the appropriate limit our results confirm the Stewart--Lyth analytic second-order calculation, and we find that their results are very accurate for inflationary models favoured by current observational constraints.
Within the MNPBEM toolbox, developed for the simulation of plasmonic nanoparticles using a boundary element method approach, we show how to include substrate and layer structure effects. We develop the methodology for solving Maxwell's equations using scalar and vector potentials within the inhomogeneous dielectric environment of a layer structure. We show that the implementation of our approach allows for fast and efficient simulations of plasmonic nanoparticles situated on top of substrates or embedded in layer structures. The new toolbox provides a number of demo files which can also be used as templates for other simulations.
We have studied the dependence of the AGN nuclear radio (1.4 GHz) luminosity on both the AGN 2-10 keV X-ray and the host-galaxy K-band luminosity. A complete sample of 1268 X-ray selected AGN (both type 1 and type 2) has been used, which is the largest catalogue of AGN belonging to statistically well defined samples where radio, X and K band information exists. At variance with previous studies, radio upper limits have been statistically taken into account using a Bayesian Maximum Likelihood fitting method. It resulted that a good fit is obtained assuming a plane in the 3D L_R-L_X-L_K space, namely logL_R= xi_X logL_X + xi_K logL_K + xi_0, having a ~1 dex wide (1 sigma) spread in radio luminosity. As already shown, no evidence of bimodality in the radio luminosity distribution was found and therefore any definition of radio loudness in AGN is arbitrary. Using scaling relations between the BH mass and the host galaxy K-band luminosity, we have also derived a new estimate of the BH fundamental plane (in the L_5GHz -L_X-M_BH space). Our analysis shows that previous measures of the BH fundamental plane are biased by ~0.8 dex in favor of the most luminous radio sources. Therefore, many AGN studies, where the BH fundamental plane is used to investigate how AGN regulate their radiative and mechanical luminosity as a function of the accretion rate, or many AGN/galaxy co-evolution models, where radio-feedback is computed using the AGN fundamental plane, should revise their conclusions.