Dephasing in two decoupled one-dimensional Bose-Einstein condensates and the subexponential decay of the interwell coherence

TL;DR

This paper explains the dephasing process in two decoupled one-dimensional Bose-Einstein condensates, attributing it to nonlinear excitation energy corrections, and revises the understanding of the coherence decay timescale.

Contribution

It offers a simplified physical model for dephasing in split condensates and revises the scaling of the decoherence time compared to previous results.

Findings

Identifies nonlinear excitation corrections as the dephasing source.

Reproduces the subexponential decay of coherence.

Provides a different scaling for the decoherence time.

Abstract

We provide a simple physical picture of the loss of coherence between two coherently split one-dimensional Bose-Einstein condensates. The source of the dephasing is identified with nonlinear corrections to the elementary excitation energies in either of the two independent condensates. We retrieve the result by Burkov, Lukin and Demler [Phys. Rev. Lett. 98, 200404 (2007)] on the subexponential decay of the cocherence for the large time, however, the scaling of the characteristic decoherence time differs.