Beyond mean-field effects in dynamics of BEC in the double-well potential

TL;DR

This paper investigates the nonlinear dynamics of a quasi-1D Bose-Einstein condensate in a double-well potential, incorporating beyond mean-field Lee-Huang-Yang corrections, and analyzes tunneling, localization, and parametric resonance phenomena.

Contribution

It introduces a two-mode model including Lee-Huang-Yang corrections for the first time in this context and validates it with numerical simulations.

Findings

Josephson oscillation frequencies match numerical results

Parametric resonance occurs under periodic barrier modulation

Lee-Huang-Yang corrections significantly affect dynamics

Abstract

The nonlinear dynamics of a quasi-1D BEC loaded in a double-well potential is studied. The beyond mean-field corrections to the energy in the form of the Lee-Huang-Yang term are taken into account. One-dimensional geometry is considered. The problem is described in the scalar approximation by the extended Gross-Pitaevskii (EGP) equation with the attractive quadratic nonlinearity, due to the Lee-Huang-Yang correction, and the effective cubic mean-field nonlinearity describing the residual intra- and inter-species interactions. To describe tunneling and localization phenomena, a two-mode model was obtained. The frequencies of the Josephson oscillations are found and confirmed by the full numerical simulations of the EGP equation. The parametric resonance in the Josephson oscillations, when the height of the barrier is periodically modulated, is studied. The predictions of the dimer model, including the case of the one-dimensional Lee-Huang-Yang superfluid, have been proven.