Parametric Resonance Phenomena in Bose-Einstein Condensates: Breaking of Macroscopic Quantum Self-Trapping

TL;DR

This paper investigates how parametric resonance affects tunneling and self-trapping phenomena in Bose-Einstein condensates within a double-well potential with an oscillating barrier, revealing conditions that enhance or suppress these effects.

Contribution

It demonstrates the critical dependence of condensate dynamics on the oscillation frequency of the barrier and identifies resonance conditions that modify tunneling and self-trapping behaviors.

Findings

Parametric resonance at twice the Josephson frequency enhances tunneling.

Resonance can suppress or reduce macroscopic quantum self-trapping.

The dynamics depend critically on the oscillation frequency of the energy barrier.

Abstract

We analyze the periodic tunneling of a Bose-Einstein condensate in a double-well potential which has an oscillating energy barrier. We show that the dynamics of the Bose condensate critically depends on the frequency $\omega$ of the oscillating energy barrier. In the regime of periodic macroscopic quantum tunneling (PMQT) with frequency $\omega_J$, the population imbalance of the condensate in the two wells can be enhanced under the condition of parametric resonance $\omega = 2 \omega_J$. Instead, in the regime of macroscopic quantum self-trapping (MQST), we find that MQST can be reduced or suppressed under the condition of parametric resonance between the frequency $\omega$ of the energy barrier and the frequency $\omega_{ST}$ of oscillation through the barrier of the very small fraction of particles which remain untrapped during MQST.