Evolution of Coherence During Ramps Across the Mott-Superfluid Phase Boundary

TL;DR

This paper investigates how correlations evolve in a Bose lattice gas during a finite-speed ramp from the Mott insulator to the superfluid phase, using a doublon-holon model and mean-field approach, with results matching experiments and DMRG in 1D.

Contribution

It introduces a mean-field doublon-holon model applicable in any dimension to study correlation growth during ramps across the Mott-superfluid boundary.

Findings

Final energy density drops rapidly for ramps shorter than one hopping time.

Longer ramps lead to a weak dependence of energy density on ramp speed.

Inelastic light scattering effects during ramps are also analyzed.

Abstract

We calculate how correlations in a Bose lattice gas grow during a finite speed ramp from the Mott to the Superfluid regime. We use an interacting doublon-holon model, applying a mean-field approach for implementing hard-core constraints between these degrees of freedom. Our solutions are valid in any dimension, and agree with experimental results and with DMRG calculations in one dimension. We find that the final energy density of the system drops quickly with increased ramp time for ramps shorter than one hopping time, $J\tau_{ramp}\lesssim 1$. For longer ramps, the final energy density depends only weakly on ramp speed. We calculate the effects of inelastic light scattering during such ramps.