Stationary states and quantum quench dynamics of Bose-Einstein condensates in a double-well potential

TL;DR

This paper investigates how pair tunneling affects stationary states and quench dynamics of Bose-Einstein condensates in a double-well potential, revealing new behaviors distinct from traditional models.

Contribution

It provides a full quantum-mechanical analysis of pair tunneling effects on BEC dynamics and stationary states in a double-well system, including the impact of Peierls phase changes.

Findings

Strong pair tunneling alters the energy spectrum of stationary states.

In weak interactions, pair tunneling shifts dynamics from Josephson oscillations to self-trapping.

In strong interactions, pair tunneling suppresses self-trapping and affects oscillation behavior.

Abstract

We consider the properties of stationary states and the dynamics of Bose-Einstein condensates (BECs) in a double-well (DW) potential with pair tunneling by using a full quantum-mechanical treatment. Furthermore, we study the quantum quench dynamics of the DW system subjected to a sudden change of the Peierls phase. It is shown that strong pair tunneling evidently influences the energy spectrum structure of the stationary states. For relatively weak repulsive interatomic interactions, the dynamics of the DW system with a maximal initial population difference evolves from Josephson oscillations to quantum self-trapping as one increases the pair tunneling strength, while for large repulsion the strong pair tunneling inhibits the quantum self-trapping. In the case of attractive interatomic interactions, strong pair tunneling tends to destroy the Josephson oscillations and quantum self-trapping, and the system eventually enters a symmetric regime of zero population difference. Finally, the effect of the Peierls phase on the quantum quench dynamics of the system is analyzed and discussed. These new features are remarkably different from the usual dynamical behaviors of a BEC in a DW potential.