Transport of a Bose gas in 1D disordered lattices at the fluid-insulator transition

TL;DR

This study explores how a 1D Bose gas transitions from fluid to insulator in disordered lattices, revealing a critical momentum and disorder threshold linked to the superfluid-Bose glass transition.

Contribution

It provides experimental evidence of a disorder-dependent critical momentum and identifies conditions where the fluid-insulator transition occurs in 1D Bose gases.

Findings

Sharp crossover from dissipative to unstable transport at critical momentum

Quantum phase slips contribute to dissipation in non-disordered lattices

Critical disorder and interaction strengths where the fluid-insulator transition occurs

Abstract

We investigate the momentum-dependent transport of 1D quasi-condensates in quasiperiodic optical lattices. We observe a sharp crossover from a weakly dissipative regime to a strongly unstable one at a disorder-dependent critical momentum. In the limit of non-disordered lattices the observations indicate a contribution of quantum phase slips to the dissipation. We identify a set of critical disorder and interaction strengths for which such critical momentum vanishes, separating a fluid regime from an insulating one. We relate our observation to the predicted zero-temperature superfluid-Bose glass transition.