Exact quantum dynamics of a bosonic Josephson junction

TL;DR

This paper presents an exact numerical study of the quantum dynamics in a one-dimensional bosonic Josephson junction, revealing significant deviations from approximate methods and uncovering complex many-body phenomena such as enhanced tunneling and rapid coherence loss.

Contribution

It provides the first exact numerical analysis of the full quantum dynamics of a bosonic Josephson junction, highlighting limitations of mean-field and approximate approaches.

Findings

Exact dynamics differ from mean-field predictions even at weak interactions.

Identifies rapid coherence loss leading to novel equilibration behavior.

Reveals complex many-body effects like enhanced tunneling.

Abstract

The quantum dynamics of a one-dimensional bosonic Josephson junction is studied by solving the time-dependent many-boson Schr\"odinger equation numerically exactly. Already for weak interparticle interactions and on short time scales, the commonly-employed mean-field and many-body methods are found to deviate substantially from the exact dynamics. The system exhibits rich many-body dynamics like enhanced tunneling and a novel equilibration phenomenon of the junction depending on the interaction, attributed to a quick loss of coherence.