Loss of superfluidity in a Bose-Einstein condensate on an optical lattice via a novel classical phase transition

TL;DR

This paper predicts a classical phase transition causing the loss of superfluidity in a Bose-Einstein condensate under resonant excitation, leading to the disappearance of interference patterns, with implications for experimental observation.

Contribution

It introduces a novel classical dynamical transition mechanism for superfluidity loss in BECs under periodic modulation of interactions.

Findings

Loss of superfluidity at resonant frequencies

Destruction of interference patterns upon expansion

Proposes experimental verification

Abstract

We predict the loss of superfluidity in a Bose-Einstein condensate (BEC) trapped in a combined optical and axially-symmetric harmonic potentials during a resonant collective excitation initiated by a periodic modulation of the atomic scattering length $a$, when the modulation frequency equals twice the radial trapping frequency or multiples thereof. This classical dynamical transition is marked by a loss of superfluidity in the BEC and a subsequent destruction of the interference pattern upon free expansion. Suggestion for future experiment is made.