Short-range coherence of a lattice Bose atom gas in the Mott insulating phase

TL;DR

This paper investigates the short-range coherence of lattice Bose gases in the Mott insulating phase, providing theoretical calculations that match experimental results and explaining deviations in interference visibility.

Contribution

It offers a quantitative theoretical analysis of interference visibility in Mott insulators, including explanations for deviations at different interaction strengths.

Findings

Quantitative agreement with experimental interference visibility data

Identification of second order correction effects at small U_0

Proposed additional sources for deviations at large U_0

Abstract

We study the short-range coherence of ultracold lattice Bose gases in the Mott insulating phase. We calculate the visibility of the interference pattern and the results agree quantitatively with the recent experimental measurement [Phys. Rev. Lett. 95, 050404 (2005)]. The visibility deviation from the inversely linear dependence on the bare on-site interaction U_0 is explained both in smaller and larger U_0. For a smaller U_0, it comes from a second order correction. For a larger U_0, except the breakdown of adiabaticity as analyzed by Gerbier et al, there might be another source to cause this deviation, which is the diversity between $U_0$ determined by the single atom Wannier function and the effective on site interaction U_eff for a multi-occupation per site.