Heavily Damped Motion of One-Dimensional Bose Gases in an Optical Lattice

TL;DR

This paper uses quantum many-body simulations to analyze the damping of dipole oscillations in one-dimensional Bose gases within optical lattices, revealing that quantum fluctuations cause overdamping before Mott insulator formation.

Contribution

First-principles simulation of strongly correlated 1D Bose gases in optical lattices across different regimes, matching experimental observations of damping behavior.

Findings

Damping of dipole oscillations occurs even in shallow lattices.

Overdamping increases with lattice depth due to quantum fluctuations.

Transition to overdamping precedes Mott insulator domain formation.

Abstract

We study the dynamics of strongly correlated one-dimensional Bose gases in a combined harmonic and optical lattice potential subjected to sudden displacement of the confining potential. Using the time-evolving block decimation method, we perform a first-principles quantum many-body simulation of the experiment of Fertig {\it et al.} [Phys. Rev. Lett. {\bf 94}, 120403 (2005)] across different values of the lattice depth ranging from the superfluid to the Mott insulator regimes. We find good quantitative agreement with this experiment: the damping of the dipole oscillations is significant even for shallow lattices, and the motion becomes overdamped with increasing lattice depth as observed. We show that the transition to overdamping is attributed to the decay of superfluid flow accelerated by quantum fluctuations, which occurs well before the emergence of Mott insulator domains.