Chaos signatures of current phase transition in a toroidal trap

TL;DR

This paper investigates how chaos signatures relate to current phase transitions in a Bose-Einstein condensate within a toroidal trap, revealing control mechanisms for atomic current and linking chaos to quantum phase changes.

Contribution

It demonstrates the control of atomic current via oscillatory driving and identifies chaos as an indicator of quantum phase transition in the system.

Findings

Oscillatory amplitude suppresses current fluctuations.

Chaos correlates with phase transition between current regimes.

Three-mode model accurately describes the system dynamics.

Abstract

In this work we demonstrate how the directed motion of atomic Bose-Einstein condensates in a toroidal trap can be controlled by applying a zero-mean oscillatory driving field. We show that due to the self-trapping effect in momentum space, the oscillatory amplitude of the current can be significantly suppressed and a nearly constant directed current can be obtained preserving the initial current values, by decreasing the driving amplitude, even when the atomic interactions are relatively small. We also reveal numerically the mean-field chaos can serve as an indicator of a quantum phase transition between the vanishing current regime and nonvanishing current regime. Our results are corroborated by an effective three-mode model, which provides an excellent account of the ratchet dynamics of the system.