Few-Body Systems最新文献

Coupling of orbital motion to a spin degree of freedom gives rise to various transport phenomena in quantum systems that are beyond the standard paradigms of classical physics. Here, we discuss features of spin-orbit dynamics that can be visualized using a classical model with two coupled angular degrees of freedom. Specifically, we demonstrate classical ‘spin’ filtering through our model and show that the interplay between angular degrees of freedom and dissipation can lead to asymmetric ‘spin’ transport.

Theoretically, in (1 + 1) dimensions, one can have Klein–Fock–Gordon–Majorana (KFGM) particles. More precisely, these are one-dimensional (1D) Klein–Fock–Gordon (KFG) and Majorana particles at the same time. In principle, the wave equations considered to describe such first-quantized particles are the standard 1D KFG equation and/or the 1D Feshbach–Villars (FV) equation, each with a real Lorentz scalar potential and some kind of Majorana condition. The aim of this paper is to analyze the latter assumption fully and systematically; additionally, we introduce specific equations and boundary conditions to characterize these particles when they lie within an interval (or on a line with a tiny hole at a point). In fact, we write first-order equations in the time derivative that do not have a Hamiltonian form. We may refer to these equations as first-order 1D Majorana equations for 1D KFGM particles. Moreover, each of them leads to a second-order equation in time that becomes the standard 1D KFG equation when the scalar potential is independent of time. Additionally, we examine the nonrelativistic limit of one of the first-order 1D Majorana equations.

N and (Delta ), the foremost member of octet and decuplet have always been under attention, providing the great platform to reveal QCD dynamics. From light to heavy hadrons, the hypercentral Constituent Quark Model (hCQM) has been used in a number of research. The research of light baryon resonances in this paper has been conducted using screened potential. The slopes and intercepts, as well as the Regge trajectories, have all been displayed. For some channels, the strong decay widths to pion have been estimated using the current masses.

The R-matrix method is widely used in scattering calculations. We present a simple extension that provides the energy and width of resonances by computing eigenvalues of a complex symmetric matrix. We briefly present the method and show some typical applications in two- and three-body systems. In particular, we discuss in more detail the (^6)He and (^6)Be three-body nuclei ((alpha +n+n) and (alpha +p+p), respectively). We show that large bases are necessary to reach convergence of the bound-state or resonance properties.

The proton charge radius and nucleon electromagnetic polarizabilities are fundamental properties probing the electromagnetic structure of the nucleons. Proton charge radius is directly related to the proton charge distribution and the nucleon electromagnetic polarizabilities characterize the response of the charge/magnetic constituents inside the nucleon to external electromagnetic fields. A precise understanding of these quantities is crucial not only for understanding how quantum chromodynamics (QCD) works in the non-perturbative QCD region but also for bound state quantum electrodynamics (QED) calculations of atomic energy levels. We discuss the experimental approaches employed in the recent decades to determine the proton charge radius and nucleon electromagnetic polarizabilities. We summarize the present status of the proton charge radius puzzle and polarizabilities measurements. Additionally, we provide prospects for various upcoming experiments.

Asymptotic normalization coefficients (ANCs) of the (0_1^+), (0_2^+), (1_1^-), (2_1^+), (3_1^-) ((l_{i th}^pi )) bound states of (^{16})O are deduced from the phase shift data of elastic (alpha )-(^{12})C scattering at low energies. S matrices of elastic (alpha )-(^{12})C scattering are constructed within cluster effective field theory (EFT), in which both bound and resonant states of (^{16})O are considered. Parameters in the S matrices are fitted to the precise phase shift data below the p-(^{15})N breakup energy for the partial waves of (l=0,1,2,3,4,5,6), and the ANCs are calculated by using the wave function normalization factors of (^{16})O propagators for (l=0,1,2,3). We review the values of ANCs, which are compared with other results in the literature, and discuss uncertainties of the ANCs obtained from the elastic (alpha )-(^{12})C scattering data in cluster EFT.

In this paper, we investigate the behavior of a quantum harmonic oscillator in the presence of a repulsive inverse-square potential within a cosmic string space-time that contains a dislocation. Our objective is to find eigenvalue solutions of this quantum system by analytically solving the Schrödinger wave equation through the confluent hypergeometric function. Furthermore, we explore the effects of a rotational frame on the quantum harmonic oscillator within this specific space-time geometry, incorporating the same repulsive potential. Following a similar procedure, we successfully determine the eigenvalue solutions for this quantum system. Importantly, our results reveal that the eigenvalue solutions are significantly influenced by four key parameters: the cosmic string, the dislocation parameter associated with the geometry, the repulsive inverse-square potential, and the constant angular speed of the rotating frame. The presence of these parameters induces a shift in the energy spectrum, thereby causing modifications to the behavior of the quantum harmonic oscillator compared to the known results.

We examine the spatial distribution of electric charges within an extended, non-conductive cylinder featuring an inner radius denoted as (r_{0}). Our investigation unveils the emergence of a distinct modified attractive-inverse square potential, arising from the intricate interplay between the electric field and the induced electric dipole moment of a neutral particle. This modified potential notably departs from the conventional inverse-square potential, showcasing an additional term proportional to (r^{-1}). As a result, we present compelling evidence for the realization of a discrete energy spectrum within this intricate system.

Cold three-body recombination between helium and silver atoms is studied using hyperspherical coordinates. The three-body Schrodinger equation, represented in the slow variable discretization approach at short distances and in the adiabatic method at large distances and using the potential-energy surface represented as the addition of realistic He-He and He-Ag pair interaction potentials, is solved using the R-matrix propagation method, in order to numerically calculate the three-body recombination rates for the He+He+Ag(rightarrow )He(_2)+Ag and He+He+Ag(rightarrow )HeAg+He processes. Not only zero-angular momentum (J=0) states but also (J>0) states are considered in the calculations, allowing for treating the recombination processes at collision energies beyond the threshold regime. The results of our calculations will be presented and discussed.

We consider the (^{3}hbox {H}) nucleus within the AAA model that includes mass identical particles interacting through a phenomenological nuclear potential. We extend the three-nucleon Hamiltonian (beta {widehat{{H}}}_{0}+{V}_{nucl.}) using the parameter (beta =m_{0}/{m^*}) that determines the variations (m^*) of the averaged nucleon mass (m_{0} = (m_{n} + m_{p})/2). It was found that the (^{3}hbox {H}) binding energy is a linear function of the mass ({m^*}/m_0) when it changes within the ranges (0.9{<}{m^*}{/m}_{0}{<}1.25). Thus, the relation between energy and mass is expressed by an analogy to the well-known formula (E=mc^{2}). This effect takes a place in small vicinity around the experimentally motivated value of the nucleon mass due to Taylor expanding the general relation (Esim 1/m). The equivalent mass of a nucleon, defined by using this energy-mass dependence, can phenomenologically describe the effect of the proton/nucleon mass difference on 3N binding energy.