Search results for "Computer Science::Digital Libraries"
showing 10 items of 133 documents
Thermodynamics of the Classical Planar Ferromagnet Close to the Zero-Temperature Critical Point: A Many-Body Approach
2012
We explore the low-temperature thermodynamic properties and crossovers of ad-dimensional classical planar Heisenberg ferromagnet in a longitudinal magnetic field close to its field-induced zero-temperature critical point by employing the two-time Green’s function formalism in classical statistical mechanics. By means of a classical Callen-like method for the magnetization and the Tyablikov-like decoupling procedure, we obtain, for anyd, a low-temperature critical scenario which is quite similar to the one found for the quantum counterpart. Remarkably, ford>2the discrimination between the two cases is found to be related to the different values of the shift exponent which governs the beha…
Interference-assisted detection of dark photon using atomic transitions
2019
Dark photon is a massive vector particle which couples to the physical photon through the kinetic mixing term. Such particles, if exist, are produced in photon beams and, in particular, in laser radiation. Due to the oscillations between the physical photon and the dark photon, the latter may be, in principle, detected in the light-shining-through-a-wall experiment. We propose a variant of this experiment where the detection of dark photons is based on the atomic transitions. The key feature of this scheme is that the detection probability is first order in the coupling constant due to the interference term in the photon and dark photon absorption amplitudes. We expect that such experiment …
Quantum Finite Automata and Logics
2006
The connection between measure once quantum finite automata (MO-QFA) and logic is studied in this paper. The language class recognized by MO-QFA is compared to languages described by the first order logics and modular logics. And the equivalence between languages accepted by MO-QFA and languages described by formulas using Lindstrom quantifier is shown.
About Graph Unions and Intersections
2020
Summary In this article the union and intersection of a set of graphs are formalized in the Mizar system [5], based on the formalization of graphs in [7].
IPHAS-selected classical Be stars
2016
We present a semi-automatic procedure to obtain fundamental physical parameters and distances of classical Be (CBe) stars, based on the Barbier-Chalonge-Divan (BCD) spectrophotometric system. Our aim is to apply this procedure to a large sample of CBe stars detected by the IPHAS photometric survey, to determine their fundamental physical parameters and to explore their suitability as galactic structure tracers. In this paper we describe the methodology used and the validation of the procedure by comparing our results with those obtained from different independent astrophysical techniques for subsamples of stars in common with other studies. We also present a test case study of the galactic …
Laser Assisted Dirac Electron in a Magnetized Annulus
2021
We study the behaviour of a charge bound on a graphene annulus under the assumption that the particle can be treated as a massless Dirac electron. The eigenstates and relative energy are found in closed analytical form. Subsequently, we consider a large annulus with radius ρ∈[5000,10,000]a0 in the presence of a static magnetic field orthogonal to its plane and again the eigenstates and eigenenergies of the Dirac electron are found in both analytical and numerical form. The possibility of designing filiform currents by controlling the orbital angular momentum and the magnetic field is shown. The currents can be of interest in optoelectronic devices that are controlled by electromagnetic radi…
Novel Method for the Direct Measurement of the τ Lepton Dipole Moments
2019
A novel method for the direct measurement of the elusive magnetic and electric dipole moments of the tau lepton is presented. The experimental approach relies on the production of tau+ leptons from Ds+ -> tau+ nu_tau decays, originated in fixed-target collisions at the LHC. A sample of polarized tau+ leptons is kinematically selected and subsequently channeled in a bent crystal. The magnetic and electric dipole moments of the tau+ lepton are measured by determining the rotation of the spin-polarization vector induced by the intense electromagnetic field between crystal atomic planes. The experimental technique is discussed along with the expected sensitivities.
The Existence of Solutions for Local Dirichlet (r(u),s(u))-Problems
2022
In this paper, we consider local Dirichlet problems driven by the (r(u),s(u))-Laplacian operator in the principal part. We prove the existence of nontrivial weak solutions in the case where the variable exponents r,s are real continuous functions and we have dependence on the solution u. The main contributions of this article are obtained in respect of: (i) Carathéodory nonlinearity satisfying standard regularity and polynomial growth assumptions, where in this case, we use geometrical and compactness conditions to establish the existence of the solution to a regularized problem via variational methods and the critical point theory; and (ii) Sobolev nonlinearity, somehow related to the spac…
Forward $J/\psi$ and very backward jet inclusive production at the LHC
2018
In the spirit of Mueller-Navelet dijet production, we propose and study the inclusive production of a forward $J/\psi$ and a very backward jet at the LHC as an observable to reveal high-energy resummation effects \`a la BFKL. We obtain several predictions, which are based on the various mechanisms discussed in the literature to describe the production of the $J/\psi$, namely, NRQCD singlet and octet contributions, and the color evaporation model.
Production of keV sterile neutrinos in supernovae: New constraints and gamma-ray observables
2019
We study the production of sterile neutrinos in supernovae, focusing in particular on the keV--MeV mass range, which is the most interesting range if sterile neutrinos are to account for the dark matter in the Universe. Focusing on the simplest scenario in which sterile neutrinos mixes only with muon or tau neutrino, we argue that the production of keV--MeV sterile neutrinos can be strongly enhanced by a Mikheyev--Smirnov--Wolfenstein (MSW) resonance, so that a substantial flux is expected to emerge from a supernova, even if vacuum mixing angles between active and sterile neutrinos are tiny. Using energetics arguments, this yields limits on the sterile neutrino parameter space that reach do…