Few-Body Systems最新文献

The dipole and quadruple Oscillator strengths for Hydrogen atom are computed under the effect of More General Exponential Cosine Screened Coulomb (MGECSC) potential which describes Debye as well as quantum plasma as its special cases. The wavefunctions are computed through numerical simulation using the accurate Numerov method. The variation of the oscillator strengths for different transitions in plasma embedded Hydrogen with respect to different parameters of the modelling potential are investigated. As per the present calculations, the dipole oscillator strengths for Debye plasma, decrease as the parameter (upmu ) increases. In contrast, for quantum plasma, the dipole oscillator strength values increase as the parameters (upmu ), b, and c of the potential increase. For quadruple oscillator strengths, few deviations are observed due to combined effect of three parameters of potential.

A number of recent references have pointed out that an N-particle system having short-range interactions at S-wave and/or P-wave unitarity can exhibit modified threshold behavior for various reactive processes. But the question of how close to unitarity one must get in order to observe such modifications has not been addressed. The present study quantifies this question by treating cases involving 3- or 4-neutrons, at the physical value of the neutron-neutron singlet scattering length (a_{s}) and at artificially altered values. One major conclusion is that the neutron-neutron scattering length is not yet sufficiently large for the 3n or 4n systems to demonstrate the unitarity threshold exponent.

We investigate the two-dimensional harmonic oscillator for a spin-1/2 particle using the Pauli equation in a ((2+1))-dimensional topologically charged Perry-Mann-type wormhole spacetime with cosmic string-type disclinations. The angular component of the Pauli spinor is a two-component plane wave. The radial differential equation includes relativistic corrections through spin-orbit coupling terms and the Darwin term. We derive the exact radial wave function expressed in terms of the Heun polynomial, along with the quantized energy levels and oscillation frequencies, incorporating corrections from spin-orbit coupling, the Darwin term, and topological effects in all cases. Furthermore, we investigate the effects of the cosmic string, global monopole, and spacetime curvature by graphically analyzing the eigenenergies and radial probability density.

Motivated by the need to model the plasma at ITER, the cross section - both total and differential - and branching ratios for mutual neutralization in collisions of (text {B}^+) with (text {H}^-) are calculated using a close coupling approach. Potential energy curves and non-adiabatic coupling elements of seven electronic states of BH in (^1Sigma ^+) symmetry are computed using the multireference configuration interaction method.

We introduce a recipe to estimate the low-energy scattering parameters of a quantum few-body system — scattering length, effective range, and shape parameter — by using only discrete state calculations. We place the system in an artificial oscillator trap of varying size and calculate the energies of the resulting discrete states close to the threshold of the system as function of the trap size. The low-energy scattering parameters are then extracted — using a simple analytic formula — from the functional dependence of these energies upon the trap size. We first test the recipe against a simple model problem and then apply it to low-energy nucleon-nucleon scattering within the nuclear Model with Explicit Mesons in one sigma-meson approximation.

In the present study, we consider the hydrogen atom confined within an impenetrable infinite cylindrical cavity of radius (rho _{0}) in the presence of a constant magnetic field (textbf{B} = B,hat{textbf{z}}) oriented along the main cylinder’s axis. In the Born-Oppenheimer approximation, anchoring the nucleus to the geometric center of the cylinder, a physically meaningful 3-parametric trial function is used to determine the ground state energy E of the system. This trial function incorporates the exact symmetries and key limiting behaviors of the problem explicitly. In particular, it does not treat the Coulomb potential nor the magnetic interaction as a perturbation. The novel inclusion of a variational cut-off factor (big (1 - big (frac{rho }{rho _0}big )^nu big )), (nu ge 1), appears to represent a significant improvement compared to the non-variational cut-off factors commonly employed in the literature. The dependence of the total energy (E=E(rho _0,,B)) and the binding energy (E_b=E_b(rho _0,,B)) on the cavity radius (rho _0 in [0.8,,5] ,)a.u. and the magnetic field strength (Bin [0.0,,1.0],)a.u. is presented in detail. The expectation values (langle rho rangle ) and (langle |z| rangle ), and the Shannon entropy in position space are computed to provide additional insights into the system’s localization. A brief discussion is provided comparing the 2D and 3D cases as well.

A quantum-mechanical wave function is complex, but all observations are real, expressible through expectation values and transition matrix elements that involve the wave functions. It can be useful to separate at the outset the amplitude and phase as real quantities that together carry the same information that is contained in the complex wave function. Two main avenues for doing so go way back in the history of the subject and have been used both for scattering and bound states. A connection is made here to gauge transformations of electrodynamics where the advent of quantum mechanics and later quantum field theory showed the central role that local gauge transformations play in physics.

In this work, we investigate the Klein-Gordon and Dirac oscillators in (2+1) dimensions under the influence of a constant magnetic field, within the framework of energy-dependent noncommutative phase space. This space is characterized by two energy-dependent deformation parameters, (theta (E)) and (eta (E)), which modify the standard phase-space algebra through generalized commutation relations. By applying the Bopp shift method and using polar coordinates, we derive exact analytical solutions for both relativistic oscillators. The relativistic energy equations and corresponding wave functions are obtained explicitly in terms of confluent hypergeometric functions for the Klein-Gordon case and associated Laguerre functions for the Dirac case. We also analyze various limiting cases, including the commutative limit, the energy-independent NC case, and the non-relativistic regime. Our results show that the energy dependence of the noncommutative parameters leads to significant modifications in the spectral structure, potentially shedding light on quantum gravitational effects at high energies.

In this paper, we explore quantum dynamics of relativistic quantum oscillator field within the framework of generalized Klein-Gordon oscillator in the context of four-dimensional wormhole with a cosmic string. The considered space-time is an example of Morris-Thorne-type traversable wormhole with topological defect. We derive a radial second-order differential equation of the generalized Klein-Gordon oscillator equation and obtain analytical solution through special functions by choosing different potential functions. In this study, we consider two distinct functions: a Coulomb- and Cornell-like potential form and solve the differential equation. As particular case, we presented the ground state energy level and the corresponding wave function of quantum oscillator fields. In fact, it is shown that the wormhole throat radius and cosmic string influences the eigenvalue solution compared to flat space results. The presence of topological defect of cosmic string breaks the degeneracy of the spectra of energy.

In this work, we investigate the quantum dynamics of a particle subject to the Morse potential within the framework of Dunkl quantum mechanics. By employing the Dunkl derivative operator–which introduces reflection symmetry–we construct a deformed Schrödinger equation and obtain exact analytical solutions using the Pekeris approximation. The resulting energy spectrum and wavefunctions reveal how Dunkl parameters alter the effective potential and vibrational states. The model is applied to several diatomic molecules, including (hbox {H}_2), HCl, and (hbox {I}_2), illustrating the impact of symmetry deformation on energy spectra. We also compute thermodynamic functions including the partition function, free energy, internal energy, entropy, and specific heat. The analysis shows that the Dunkl deformation induces distinct thermal behavior and offers a tunable approach to molecular modeling. These results highlight the potential of the Dunkl formalism as a useful tool for extending conventional quantum models and for exploring symmetry-deformed systems in molecular physics and quantum thermodynamics.