Probing the Bose-Glass--Superfluid Transition using Quantum Quenches of Disorder

TL;DR

This study investigates the transition from superfluid to Bose glass phases in a disordered quantum system by using quantum quenches and confirms the phase boundary through simulations and experimental measurements.

Contribution

It introduces a method of probing the Bose-glass--superfluid transition via quantum quenches and correlates excitations with the phase boundary.

Findings

Threshold behavior in disorder strength indicates phase transition.

Simulations confirm the phase boundary matches experimental observations.

Disappearance of adiabatic timescale in the Bose glass regime.

Abstract

We probe the transition between superfluid and Bose glass phases using quantum quenches of disorder in an ultracold atomic lattice gas that realizes the disordered Bose-Hubbard model. Measurements of excitations generated by the quench exhibit threshold behavior in the disorder strength indicative of a phase transition. Ab-initio quantum Monte Carlo simulations confirm that the appearance of excitations coincides with the equilibrium superfluid--Bose-glass phase boundary at different lattice potential depths. By varying the quench time, we demonstrate the disappearance of an adiabatic timescale compared with microscopic parameters in the BG regime.