Soliton dynamics of a high-density Bose-Einstein condensate subject to a time varying anharmonic trap

TL;DR

This study investigates the complex soliton dynamics of a high-density Bose-Einstein condensate in a time-varying anharmonic trap, revealing novel fragmentation phenomena and validating a variational approach with numerical simulations.

Contribution

It introduces a modified Gross-Pitaevskii equation including high-density effects and analyzes soliton behavior under dynamic traps using variational and numerical methods.

Findings

Center of pulse oscillates as predicted by VA

Fragmentation and regeneration (FR) phenomenon observed

FR is suppressed by quadratic potential variation but persists with cubic variation

Abstract

In this paper we study the soliton dynamics of a high-density Bose-Einstein condensate (BEC) subject to a time-oscillating trap. The behavior of the BEC is described with a modified Gross-Pitaevskii equation (mGPE) which takes into account three-body losses, atomic feeding and quantum fluctuations (up to a novel high-density term). A variational approximation (VA) is used to study the behavior of a Gaussian pulse in a static double-well potential. Direct numerical solutions of the mGPE corroborate that the center of the pulse exhibits an oscillatory behavior (as the VA predicts), and show a novel phenomenon of fragmentation and regeneration (FR). It is shown that this FR process is destroyed if we consider a potential with a time-dependent quadratic term, but the FR survives if the time dependence is introduced in a cubic term. Comparison between the VA and the numerical solution revealed an excellent agreement when the oscillations of the pulse remain in one of the potential wells. The effects of the quantum fluctuating terms on the FR process are studied. Finally, variational results using a supergaussian trial function are obtained.