Quantum dynamics of instability-induced pulsations of a Bose-Einstein condensate in an optical lattice

TL;DR

This paper investigates the quantum dynamics of a Bose-Einstein condensate in an optical lattice, revealing pulsating instabilities and the influence of quantum fluctuations, especially at higher interaction strengths.

Contribution

It introduces an approximate quantum fluctuation model for BEC dynamics in optical lattices, highlighting quantum effects on pulsating instabilities.

Findings

Pulsating dynamical instability causes atoms to periodically gather and disperse.

Quantum fluctuations affect the stability and behavior of the condensate.

Quantum effects become more significant with increased interaction strength.

Abstract

We study the dynamics of a Bose-Einstein condensate in a one-dimensional optical lattice in the limit of weak atom-atom interactions, including an approximate model for quantum fluctuations. A pulsating dynamical instability in which atoms periodically collect together and subsequently disperse back into the initial homogeneous state may occur in the time evolution. We take into account the quantum fluctuations within the truncated Wigner approximation. We observe that the quasiperiodic behavior still persists for a single realization that represents a typical experimental outcome, but ensemble averages show various manifestations of quantum fluctuations. Quantum effects become more prominent when the effective interaction strength is increased.