Decay of superfluid currents in the interacting one-dimensional Bose gas

TL;DR

This paper investigates how superfluid currents in a one-dimensional Bose gas decay, revealing that interaction strength influences metastability and that the Landau critical velocity approaches zero in large systems, with implications for experiments.

Contribution

It provides a detailed analysis of superfluid current decay in a 1D Bose gas, highlighting the role of interactions and the zero Landau critical velocity in the thermodynamic limit.

Findings

Stronger interactions lead to faster current decay.

Landau critical velocity is zero in the thermodynamic limit.

Decay rates of ring currents can be experimentally observed.

Abstract

We examine the superfluid properties of a 1D Bose gas in a ring trap based on the model of Lieb and Liniger. While the 1D Bose gas has nonclassical rotational inertia and exhibits quantization of velocities, the metastability of currents depends sensitively on the strength of interactions in the gas: the stronger the interactions, the faster the current decays. It is shown that the Landau critical velocity is zero in the thermodynamic limit due to the first supercurrent state, which has zero energy and finite probability of excitation. We calculate the energy dissipation rate of ring currents in the presence of weak defects, which should be observable on experimental time scales.