Many-site coherence revivals in the extended Bose-Hubbard model and the Gutzwiller approximation

TL;DR

This paper studies how long-range interactions affect coherence revivals in optical lattices, revealing limitations of the Gutzwiller approximation and proposing a modified approach for better predictions.

Contribution

It demonstrates the impact of long-range interactions on coherence revivals and introduces a modified Gutzwiller ansatz that improves predictive accuracy.

Findings

Revival peaks are strongly attenuated by moderate long-range interactions.

Standard Gutzwiller wavefunction fails to predict collapse and revival oscillations accurately.

Modified Gutzwiller ansatz reproduces analytical results in the zero tunneling limit.

Abstract

We investigate the collapse and revival of first-order coherence in deep optical lattices when long-range interactions are turned on, and find that the first few revival peaks are strongly attenuated already for moderate values of the nearest-neighbor interaction coupling. It is shown that the conventionally employed Gutzwiller wavefunction, with only onsite-number dependence of the variational amplitudes, leads to incorrect predictions for the collapse and revival oscillations. We provide a modified variant of the Gutzwiller ansatz, reproducing the analytically calculated time dependence of first-order coherence in the limit of zero tunneling.