Chaos assisted many-body tunnelling

TL;DR

This paper investigates how chaos influences many-body tunnelling in coupled Bose-Josephson junctions, revealing that chaos can significantly enhance tunnelling rates and cause large fluctuations with small parameter changes.

Contribution

It demonstrates that chaos enhances many-body tunnelling and causes large fluctuations in tunnelling rates in coupled Bose-Josephson systems.

Findings

Chaos enhances many-body tunnelling gaps.

Tunnelling rates fluctuate over orders of magnitude.

Small parameter changes cause large tunnelling rate variations.

Abstract

We study the interplay of chaos and tunnelling between two weakly-coupled Bose-Josephson junctions. The classical phase space of the composite system has a mixed structure including quasi-integrable self-trapping islands for particles and excitations, separated by a chaotic sea. We show that the many-body dynamical tunnelling gap between macroscopic Schr\"odinger cat states supported by these islands is chaos-enhanced. The many-body tunnelling rate fluctuates over several orders of magnitude with small variations of the system parameters or the particle number.