Nonequilibrium Josephson oscillations in Bose-Einstein condensates without dissipation

TL;DR

This paper investigates the nonequilibrium Josephson oscillations in Bose-Einstein condensates within a double-well trap, revealing sustained undamped oscillations up to a certain time and predicting their eventual destruction by Rabi oscillations.

Contribution

It provides a detailed field theoretical analysis of Josephson oscillations without dissipation, explaining experimental observations and predicting the transition to Rabi oscillations.

Findings

Multiple undamped Josephson oscillations can persist up to a characteristic time.

Beyond this time, Rabi oscillations dominate the dynamics.

Self-trapped BEC states are predicted to be destroyed by Rabi oscillations.

Abstract

We perform a detailed field theoretical study of nonequilibrium Josephson oscillations between interacting Bose-Einstein condensates confined in a finite-size double-well trap. We find that the Josephson junction can sustain multiple undamped Josephson oscillations up to a characteristic time scale $\tau_c$ without quasipartcles being excited in the system. This may explain recent related experiments. At larger times the dynamics of the junction is governed by fast Rabi oscillations between the descrete quasiparticle levels. We predict that a selftrapped BEC state will be destroyed by these Rabi oscillations.