Dynamics of Bose-Einstein Recondensation in Higher Bands

TL;DR

This paper models the non-equilibrium dynamics of Bose-Einstein condensation in higher energy bands of optical lattices, detailing a three-phase relaxation process from initial evaporation to recondensation.

Contribution

It provides a theoretical framework for understanding the kinetics of BEC in higher bands, including phase transitions and time-scale predictions, inspired by recent experimental setups.

Findings

Identification of three distinct kinetic phases

Quantitative estimates of relaxation time-scales

Predictions for experimental verification

Abstract

Motivated by recent experiments, we explore the kinetics of Bose-Einstein condensation in the upper band of a double well optical lattice. These experiments engineer a non-equilibrium situation in which the highest energy state in the band is macroscopically occupied. The system subsequently relaxes and the condensate moves to the lowest energy state. We model this process, finding that the kinetics occurs in three phases: The condensate first evaporates, forming a highly non-equilibrium gas with no phase coherence. Energy is then redistributed among the noncondensed atoms. Finally the atoms recondense. We calculate the time-scales for each of these phases, and explain how this scenario can be verified through future experiments.