Pulsating instability of a Bose-Einstein condensate in an optical lattice

TL;DR

This paper numerically investigates a pulsating dynamical instability in a weakly interacting Bose-Einstein condensate within an optical lattice, revealing periodic peaks in site occupation and linking the phenomenon to integrability remnants.

Contribution

It introduces the concept of pulsating instability in BECs in optical lattices and connects it to underlying integrability properties, providing new insights into condensate dynamics.

Findings

Identification of pulsating instability in weakly interacting BECs

Periodic formation and dissolution of occupation peaks

Relation of instability to integrability remnants

Abstract

We find numerically that in the limit of weak atom-atom interactions a Bose-Einstein condensate in an optical lattice may develop a pulsating dynamical instability in which the atoms nearly periodically form a peak in the occupation numbers of the lattice sites, and then return to the unstable initial state. Multiple peaks behaving similarly may also occur. Simple arguments show that the pulsating instability is a remnant of integrability, and give a handle on the relevant physical scales.