Steering Bose-Einstein condensates despite time symmetry

TL;DR

This paper demonstrates that Bose-Einstein condensates can be directed to move in a specific direction within symmetric oscillating potentials, with the effect depending on atom interactions and validated through both mean-field and many-body models.

Contribution

It reveals a novel mechanism for directed transport in symmetric potentials driven by atom interactions, supported by a three-mode model and many-body simulations.

Findings

Directed current occurs only above a critical interaction strength.

Three-mode model accurately describes the phenomenon.

Mean-field approximation validity extends over increasing time with more atoms.

Abstract

A Bose-Einstein condensate in an oscillating spatially asymmetric potential is shown to exhibit a directed current for unbiased initial conditions despite time symmetry. This phenomenon occurs only if the interaction between atoms, treated in mean-field approximation, exceeds a critical value. Our findings can be described with a three-mode model (TMM). These TMM results corroborate well with a many-body study over a time scale which increases with increasing atom number. The duration of this time scale probes the validity of the used mean-field approximation.