Classical route to ergodicity and scarring phenomena in a two-component Bose-Josephson junction

TL;DR

This paper explores how a binary Bose-Josephson junction exhibits complex collective dynamics, ergodicity, and quantum scars, linking classical and quantum behaviors through interaction tuning and experimental signatures.

Contribution

It reveals the connection between classicality, quantum scars, and ergodicity in a two-component BJJ, highlighting the role of interactions and experimental observables.

Findings

Rich Josephson dynamics and transitions controlled by interactions

Entanglement spectrum reveals classicality and scar formation

Ergodicity and scarring probed via auto-correlation and phase fluctuations

Abstract

We consider a Bose-Josephson junction (BJJ) formed by a binary mixture of ultracold atoms to investigate the manifestation of coherent collective dynamics on ergodicity and quantum scars, unfolding the connection between them. By tuning the inter- and intra-species interaction, we demonstrate a rich variety of Josephson dynamics and transitions between them, which plays a crucial role in controlling the overall ergodic behavior. The signature of underlying classicality is revealed from the entanglement spectrum, which also elucidates the formation of quantum scars of unstable steady states and of periodic orbits leading to athermal behavior. The degree of ergodicity across the energy band and scarring phenomena can be probed from the auto-correlation function as well from the phase fluctuation of the condensates, which has relevance in cold atom experiments.