Velocity-dependent quantum phase slips in 1D atomic superfluids

TL;DR

This paper experimentally investigates quantum phase slips in 1D ultracold atomic superfluids, revealing a crossover from thermally-assisted to purely quantum phase slips through velocity-dependent dissipation measurements.

Contribution

It provides the first experimental evidence of quantum phase slips in ultracold quantum gases and characterizes their velocity and temperature dependence.

Findings

Observation of a crossover from temperature-dependent to velocity-dependent dissipation.

Evidence supporting the transition from thermally-assisted to quantum phase slips.

Quantitative measurement of phase slip nucleation rates in ultracold gases.

Abstract

Quantum phase slips are the primary excitations in one-dimensional superfluids and superconductors at low temperatures but their existence in ultracold quantum gases has not been demonstrated yet. We now study experimentally the nucleation rate of phase slips in one-dimensional superfluids realized with ultracold quantum gases, owing along a periodic potential. We observe a crossover between a regime of temperature-dependent dissipation at small velocity and interaction and a second regime of velocity-dependent dissipation at larger velocity and interaction. This behavior is consistent with the predicted crossover from thermally-assisted quantum phase slips to purely quantum phase slips.