Interaction-modulated tunneling dynamics in a mixture of Bose-Einstein condensates

TL;DR

This paper investigates how interactions between two Bose-Einstein condensates influence tunneling dynamics in a double-well potential, revealing complex behaviors like enhanced self-trapping and tunable oscillations through coupled numerical analysis.

Contribution

It introduces a coupled model of two BECs in different potentials, demonstrating interaction-driven modulation of tunneling dynamics and phase transitions.

Findings

Interaction causes non-linear tunneling oscillations.

Enhanced macroscopic self-trapping observed.

Transition between Josephson oscillation and self-trapping identified.

Abstract

We study the interaction-modulated tunneling dynamics of a Bose-Einstein condensate (BEC) in a deep double-well potential, where the tunneling between the two wells is modulated by another BEC trapped in a harmonic potential symmetrically positioned at the center of the double-well potential. The inter-species interactions couple the dynamics of the two BECs, which give rise to interesting features in the tunneling oscillations. Adopting a two-mode approximation for the BEC in the double-well potential and coupling it with the Gross-Pitaevskii equation of the harmonically trapped BEC, we numerically investigate the coupled dynamics of the BEC mixture, and map out the phase diagram of the tunneling dynamics. We show that the dynamical back action of the BEC in the harmonic trap leads to strong non-linearity in the oscillations of the BEC in the double-well potential, which enriches the system dynamics, and enhances macroscopic self trapping. The transition between the Josephson oscillation and the self-trapping dynamics can be identified by monitoring the oscillation frequency of the double-well BEC. Our results suggest the possibility of tuning the tunneling dynamics of BECs in double-well potentials.