ShantanuT01/DACTYL-Pretraining huggingface dataset:
Quasi-set theory provides a mathematical background for dealing with collections of indistinguishable elementary particles. In this paper, we show how to obtain the quantum statistics into the scope of quasi-set theory and discuss the Helium atom, which represents the simplest example where indistinguishability plays an important role. A brief discussion about indistinguishability and interference is also presented as well as other related lines of work. One of the advantages of our approach is that one of the most basic principles of quantum theory, namely, the Indistinguishability Postulate, does not need to be assumed even implicetely in the axiomatic basis of quantum mechanics.
The crystal and magnetic structures of AlFe2B2 have been studied with a combination of X-ray and neutron diffraction and electronic structure calculations. The magnetic and magnetocaloric properties have been investigated by magnetisation measurements. The samples have been produced using high temperature synthesis and subsequent heat treatments. The compound crystallises in the orthorhombic crystal system Cmmm and it orders ferromagnetically at 285 K through a second order phase transition. At temperatures below the magnetic transition the magnetic moments align along the crystallographic $a$-axis. The magnetic entropy change from 0 to 800 kA/m was found to be -1.3 J/K kg at the magnetic transition temperature.
Numerical approximate computation can solve large and complex problems fast. It has the advantage of high efficiency. However it only gives approximate results, whereas we need exact results in many fields. There is a gap between approximate computation and exact results. In this paper, we build a bridge by which exact results can be obtained by numerical approximate computations.
We present a new method based on a Bayesian hierarchical model to extract constraints on cosmological parameters from SNIa data obtained with the SALT-II lightcurve fitter. We demonstrate with simulated data sets that our method delivers tighter statistical constraints on the cosmological parameters over 90% of the time, that it reduces statistical bias typically by a factor ~ 2-3 and that it has better coverage properties than the usual chi-squared approach. As a further benefit, a full posterior probability distribution for the dispersion of the intrinsic magnitude of SNe is obtained. We apply this method to recent SNIa data, and by combining them with CMB and BAO data we obtain Omega_m=0.28 +/- 0.02, Omega_Lambda=0.73 +/- 0.01 (assuming w=-1) and Omega_m=0.28 +/- 0.01, w=-0.90 +/- 0.05 (assuming flatness; statistical uncertainties only). We constrain the intrinsic dispersion of the B-band magnitude of the SNIa population, obtaining sigma_mu^int = 0.13 +/- 0.01 [mag]. Applications to systematic uncertainties will be discussed in a forthcoming paper.
It is suggested that the observed excess of muons in studies of $p \bar{p}$ collisions at $\sqrt{s} = 1.96$ TeV arises from the decay of doubly-charged bosons. Such particles are predicted in the 3-3-1 model where the electroweak gauge group is extended to $SU(3) \times U(1)$.
We prove a `Weierstrass Preparation Theorem' and develop an explicit descent formalism in the context of Whitehead groups of non-commutative Iwasawa algebras. We use these results to describe the precise connection between the main conjecture of non-commutative Iwasawa theory (in the sense of Coates, Fukaya, Kato, Sujatha and Venjakob) and the equivariant Tamagawa number conjecture. The latter result is both a converse to a theorem of Fukaya and Kato and also provides an important means of deriving explicit consequences of the main conjecture.
Double-mode RR Lyr type stars are important for studies of properties of horizontal-branch stars. In particular, two periods coupled with spectral properties give a mass estimate that is independent of evolutionary models. Here, we present 59 new Galactic double-mode RR Lyr stars found in the LINEAR survey data with the fundamental radial mode and the first overtone exited (RRd stars). These stars may be useful for constraining the mass-metallicity relation for field horizontal-branch stars. Also, new RRd stars found in the LMC by EROS-II are verified. We present the updated Petersen diagram and the distribution of the fundamental mode periods. Comments on selected variable stars from LINEAR and LMC EROS-II surveys are also presented, including very rare objects: the third known mode-switching RR Lyr and Cepheid pulsating simultaneously in three radial modes.
Event-by-event fluctuations of the net baryon number and electric charge in nucleus-nucleus collisions are studied in Pb+Pb at SPS energies within the HSD transport model. We reveal an important role of the fluctuations in the number of target nucleon participants. They strongly influence all measured fluctuations even in the samples of events with rather rigid centrality trigger. This fact can be used to check different scenarios of nucleus-nucleus collisions by measuring the multiplicity fluctuations as a function of collision centrality in fixed kinematical regions of the projectile and target hemispheres. The HSD results for the event-by-event fluctuations of electric charge in central Pb+Pb collisions at 20, 30, 40, 80 and 158 A GeV are in a good agreement with the NA49 experimental data and considerably larger than expected in a quark-gluon plasma. This demonstrate that the distortions of the initial fluctuations by the hadronization phase and, in particular, by the final resonance decays dominate the observable fluctuations.
We present the first catalogue of known variable stars in open cluster regions and with up to two times the given cluster radius. This gives basic information about the distribution of variable stars in cluster fields for the complete sky. Knowledge of the variable star contents in open clusters is a significant advantage in their study. Analysing variability of cluster members and fields stars as well, allows us to study the characteristics of stars and clusters together. This catalogue of variable stars in open cluster fields is the first step in supporting such studies. We took all variable and suspected variable stars into account from the most complete collection, "The AAVSO Variable Star Index", and did a cross-match of these stars with the most complete catalogue of galactic open clusters named DAML02. Our on-line catalogue presently contains 18 065 variable stars. We present the basic statistical distribution according to types of variability.
Context: In 2004, changes in the radio morphology of the Be/X-ray binary system LSI+61303 suggested that it is a precessing microquasar. In 2006, a set of VLBA observations performed throughout the entire orbit of the system were not used to study its precession because the changes in radio morphology could tentatively be explained by the alternative pulsar model. However, a recent radio spectral index data analysis has confirmed the predictions of the two-peak microquasar model, which therefore does apply in LSI+61303. Aims: We revisit the set of VLBA observations performed throughout the orbit to determine the precession period and improve our understanding of the physical mechanism behind the precession. Methods: By reanalyzing the VLBA data set, we improve the dynamic range of images by a factor of four, using self-calibration. Different fitting techniques are used and compared to determine the peak positions in phase-referenced maps. Results: The improved dynamic range shows that in addition to the images with a one-sided structure, there are several images with a double-sided structure. The astrometry indicates that the peak in consecutive images for the whole set of observations describes a well-defined ellipse, 6-7 times larger than the orbit, with a period of about 28 d. Conclusions: A double-sided structure is not expected to be formed from the expanding shocked wind predicted in the pulsar scenario. In contrast, a precessing microquasar model can explain the double- and one-sided structures in terms of variable Doppler boosting. The ellipse defined by the astrometry could be the cross-section of the precession cone, at the distance of the 8.4 GHz-core of the steady jet, and 28d the precession period.
A calculation of the leading isospin-breaking contributions to the B -> K^* gamma decay amplitudes based on the QCD factorization approach is presented. They arise at order Lambda/m_b in the heavy-quark expansion and are due to annihilation contributions from 4-quark operators, the chromo-magnetic dipole operator, and charm penguins. In the Standard Model the decay rate for B^0 -> K^{*0} gamma is predicted to be about 10-20 % larger than that for B^- -> K^{*-} gamma. Isospin-breaking effects are a sensitive probe of the penguin sector of the effective weak Hamiltonian. New Physics models in which the hierarchy of B -> K^* gamma decay rates is either flipped or greatly enhanced could be ruled out with more precise data.
The peculiar uncertainty or randomness of quantum measurements stems from coherence, whose information-theoretic characterization is currently under investigation. Under the resource theory of coherence, it is interesting to investigate interpretations of coherence measures and the interplay with other quantum properties, such as quantum correlations and intrinsic randomness. Coherence can be viewed as the resource for the intrinsic randomness in the measurement outcomes of a state in the computational basis. We observed in our previous work that the coherence of formation, which measures the asymptotic coherence dilution rate, indeed quantifies the uncertainty of a (classical) correlated party about the system measurement outcome. In this work, we re-derive the result from a quantum point of view and then connect the intrinsic randomness to the relative entropy of coherence, another important coherence measure that quantifies the asymptotic distillable coherence. Even though there does not exist bound coherent states, these two intrinsic randomness quantified by coherence of formation and the relative entropy of coherence are different. Interestingly, we show that this gap is equal to the quantum discord, a general form of quantum correlations, in the state of the system of interest and the correlated party, after a local measurement on the former system.
We present an analysis of the evolution of the central mass-density profile of massive elliptical galaxies from the SLACS and BELLS strong gravitational lens samples over the redshift interval z ~ 0.1-0.6, based on the combination of strong-lensing aperture mass and stellar velocity-dispersion constraints. We find a significant trend towards steeper mass profiles (parameterized by the power-law density model with rho ~ r^[-gamma]) at later cosmic times, with magnitude d<gamma>/dz = -0.60 +/- 0.15. We show that the combined lens-galaxy sample is consistent with a non-evolving distribution of stellar velocity dispersions. Considering possible additional dependence of <gamma> on lens-galaxy stellar mass, effective radius, and Sersic index, we find marginal evidence for shallower mass profiles at higher masses and larger sizes, but with a significance that is sub-dominant to the redshift dependence. Using the results of published Monte Carlo simulations of spectroscopic lens surveys, we verify that our mass-profile evolution result cannot be explained by lensing selection biases as a function of redshift. Interpreted as a true evolutionary signal, our result suggests that major dry mergers involving off-axis trajectories play a significant role in the evolution of the average mass-density structure of massive early-type galaxies over the past 6 Gyr. We also consider an alternative non-evolutionary hypothesis based on variations in the strong-lensing measurement aperture with redshift, which would imply the detection of an "inflection zone" marking the transition between the baryon-dominated and dark-matter halo-dominated regions of the lens galaxies. Further observations of the combined SLACS+BELLS sample can constrain this picture more precisely, and enable a more detailed investigation of the multivariate dependences of galaxy mass structure across cosmic time.
We present polarimetric imaging of the protoplanetary nebula RAFGL 2688 obtained at 4.5 microns with the Infrared Space Observatory (ISO). We have deconvolved the images to remove the signature of the point spread function of the ISO telescope, to the extent possible. The deconvolved 4.5 micron image and polarimetric map reveal a bright point source with faint, surrounding reflection nebulosity. The reflection nebula is brightest to the north-northeast, in agreement with previous ground- and space-based infrared imaging. Comparison with previous near-infrared polarimetric imaging suggests that the polarization of starlight induced by the dust grains in RAFGL 2688 is more or less independent of wavelength between 2 microns and 4.5 microns. This, in turn, indicates that scattering dominates over thermal emission at wavelengths as long as ~5 microns, and that the dust grains have characteristic radii < 1 micron.
We present a survey for metal absorption systems traced by neutral oxygen over $3.2 < z < 6.5$. Our survey uses Keck/ESI and VLT/X-Shooter spectra of 199 QSOs with redshifts up to 6.6. In total we detect 74 O I absorbers, of which 57 are separated from the background QSO by more than 5000 km/s. We use a maximum likelihood approach to fit the distribution of O I $\lambda$1302 equivalent widths in bins of redshift, and from this determine the evolution in number density of absorbers with $W_{1302} > 0.05$ angstroms. We find that the number density does not monotonically increase with decreasing redshift, as would naively be expected from the buildup of metal-enriched circumgalactic gas with time. The number density over $4.9 < z < 5.7$ is a factor of 1.7--4.1 lower (68% confidence) than over $5.7 < z < 6.5$, with a lower value at $z < 5.7$ favored with 99% confidence. This decrease suggests that the fraction of metals in a low-ionization phase is larger at $z \sim 6$ than at lower redshifts. Absorption from highly ionized metals traced by C IV is also weaker in higher-redshift O I systems, supporting this picture. The evolution of O I absorbers implies that metal-enriched circumgalactic gas at $z \sim 6$ is undergoing an ionization transition driven by a strengthening ultraviolet background. This in turn suggests that the reionization of the diffuse intergalactic medium may still be ongoing at or only recently ended by this epoch.
This work describes how to implement a non-local xor function for coherent-state qubit using only linear optics. The setup proposed does not use gates based on teleportation and it has probability of success equal to 0.5, in the lossless case, when the necessary entangled state is available. The key element that makes possible the realization of the non-local xor function is a tripartite GHZ-type entangled coherent state. Its generation is proposed firstly using an ideal lossless setup and secondly considering the decoherence caused by losses in the optical devices.
We study the Chandrasekhar variational model for neutron stars, with or without an external potential. We prove the existence of minimizers when the attractive interaction strength $\tau$ is strictly smaller than the Chandrasekhar limit $\tau_c$ and investigate the blow-up phenomenon in the limit $\tau\uparrow \tau_{c}$. We show that the blow-up profile of the minimizer(s) is given by the Lane-Emden solution.
In the next years the FERMI gamma ray telescope and the Cherenkov telescopes will put very stringent constraints to models of gamma ray emission from galaxy clusters providing crucial information on relativistic particles in the inter-galactic-medium. We derive the broad band non-thermal spectrum of galaxy clusters in the context of general calculations in which relativistic particles (protons and secondary electrons due to proton-proton collisions) interact with MHD turbulence generated in the cluster volume during cluster mergers, and discuss the importance of future gamma ray observations.
Here we make an attempt to extend the idea of generalized Hawking temperature and modified Bekenstein entropy at the event horizon in a fractal universe. The modified Hawking temperature and Bekenstein entropy are considered in the governing Friedmann equations, which is modified in the background of a fractal universe. The validity of the Generalized second law of thermodynamics\,(GSLT) and Thermodynamic Equilibrium\,(TE) have been examined and compared graphically in a fractal universe filled with a perfect fluid having the constant equation of state in three different generalized Bekenstein system.
In 1914, F. Hausdorff defined a metric on the set of closed subsets of a metric space $X$. This metric induces a topology on the set $H$ of compact subsets of $X$, called the Hausdorff topology. We show that the topological space $H$ represents the functor on the category of sequential topological spaces taking $T$ to the set of closed subspaces $Z$ of $T \times X$ for which the projection $\pi_1 : Z \to T$ is open and proper. In particular, the Hausdorff topology on $H$ depends on the metric space $X$ only through the underlying topological space of $X$. The Hausdorff space $H$ provides an analog of the Hilbert scheme in topology. As an example application, we explore a certain quotient construction, called the Hausdorff quotient, which is the analog of the Hilbert quotient in algebraic geometry.
A study of conformally flat but non flat Bianchi type I and cylindrically symmetric static space-times according to proper projective symmetry is given by using some algebraic and direct integration techniques. It is shown that the special class of the above space-times admit proper projective vector fields.
Developing a theory that can describe everything in the universe is of great interest, and is closely relevant to M-theory, neutrino oscillation and charge-parity (CP) violation. Although M-theory is claimed as a grand unified theory, it has not been tested by any direct experiment. Here we show that existing neutrino oscillation experimental data supports one kind of high dimensional unified theory, such as M-theory. We propose a generalization of the tri-bimaximal neutrino mixing ansatz, and we find that the latest neutrino oscillation experimental data constraints dimension in a range between 10.46 and 12.93 containing 11, which is an important prediction of M-theory. This ansatz naturally incorporates the fractal feature of the universe and leptonic CP violation into the resultant scenario of \textit{fractal} nearly tri-bimaximal flavor mixing. We also analyze the consequences of this new ansatze on the latest experimental data of neutrino oscillations, and this theory matches the experimental data. Furthermore, an approach to construct lepton mass matrices in fractal universe under permutation symmetry is discussed. The proposed theory opens an unexpected window on the physics beyond the Standard Model.
We present a detailed low-energy muon spin rotation and x-ray magnetic circular dichroism (XMCD) investigation of the magnetic structure in ultra-thin tetragonal (T)-CuO films. The measured muon-spin polarization decay indicates an antiferromagnetic (AFM) order with a transition temperature higher than 200K. The XMCD signal obtained around the Cu $L_{2,3}$ edges indicates the presence of pinned Cu$^{2+}$ moments that are parallel to the sample surface, and additionally, isotropic paramagnetic moments. The pinning of some of the Cu moments is caused by an AFM ordering consisting of moments that lie most likely in the plane of the film. Moreover, pinned moments show a larger orbital magnetic moment contribution with an approximate ratio of $m_{orb}/m_{spin} = 2$, indicating that these spins are located at sites with reduced symmetry. Some fractions of the pinned moments remain pinned from an AFM background even at 360K, indicating that $T_N >$ 360K. A simple model could explain qualitatively these experimental findings; however, it is in contrast to theoretical predictions, showing that the magnetic properties of ultra-thin T-CuO films differ from bulk expectations and is more complex.
Due to the large cross-modality discrepancy between 2D sketches and 3D shapes, retrieving 3D shapes by sketches is a significantly challenging task. To address this problem, we propose a novel framework to learn a discriminative deep cross-modality adaptation model in this paper. Specifically, we first separately adopt two metric networks, following two deep convolutional neural networks (CNNs), to learn modality-specific discriminative features based on an importance-aware metric learning method. Subsequently, we explicitly introduce a cross-modality transformation network to compensate for the divergence between two modalities, which can transfer features of 2D sketches to the feature space of 3D shapes. We develop an adversarial learning based method to train the transformation model, by simultaneously enhancing the holistic correlations between data distributions of two modalities, and mitigating the local semantic divergences through minimizing a cross-modality mean discrepancy term. Experimental results on the SHREC 2013 and SHREC 2014 datasets clearly show the superior retrieval performance of our proposed model, compared to the state-of-the-art approaches.
Neutron and proton driplines of single-$\Lambda$ and double-$\Lambda$ hypernuclei, $\Xi^{-}$ hypernuclei as well as normal nuclei are studied within a relativistic mean field approach using an extended form of the FSU Gold Lagrangian density. Hyperons are found to produce bound nuclei beyond the normal nuclear driplines. Radii are found to decrease in hypernuclei near the driplines, in line with observations in light $\Lambda$ hypernuclei near the stability valley, The inclusion of a $\Xi^{-}$ introduces a much larger change in radii than one or more $\Lambda$'s.
Cosmological precision data can be used to set very strict constraints on Axions and Axion-like particles (ALPs) produced thermally in the big bang. We briefly review the known bounds and propose two new constraints for Axions and ALPs decaying in the early universe, based upon the concomitant dilution of baryon and neutrino densities, using WMAP7 and other cosmological data.
Context. There are more than 3000 confirmed and probable known Galactic planetary nebulae, but central star spectroscopic information is available for only 13% of them. Aims. We undertook a spectroscopic survey of central stars of PNe to identify their spectral types. Methods. We performed spectroscopic observations, at low resolution, with the 2-m telescope at CASLEO, Argentina. Results. We present the spectra of 46 central stars of PNe, most of them are OB-type and emission-line stars.
In a multidimensional model with several scalar fields and an m-form we deal with classical spherically symmetric solutions with one (electric or magnetic) p-brane and Ricci-flat internal spaces and the corresponding solutions to the Wheeler--DeWitt (WDW) equation. Classical black holes are considered and their quantum analogues (e.g. for M2 and M5 extremal solutions in D =11 supergravity, electric and magnetic charges in D=4 gravity) are suggested when the curvature coupling in the WDW equation is zero.
In this paper a cellular automata model for one-lane traffic flow is presented. A new set of rules is proposed to better capture driver reactions to traffic that are intended to preserve safety on the highway. As a result, drivers behavior is derived from an analysis that determines the most appropriate action for a vehicle based on the distance from the vehicle ahead of it and the velocities of the two neighbor vehicles. The model preserves simplicity of CA rules and at the same time makes the results closer to real highway behavior. Simulation results exhibit the three states observed in real traffic flow: Free-flow states, synchronized states, and stop-and-go states.