Persistent currents in a bosonic mixture in the ring geometry

TL;DR

This paper investigates the stability of persistent currents in a two-species bosonic mixture confined to a one-dimensional ring, extending classical criteria and revealing enhanced stability at higher angular momenta.

Contribution

It extends Bloch's criterion to two-species systems, linking it to Landau's criterion, and shows increased stability of persistent currents at higher angular momenta.

Findings

Persistent currents can be stable at certain angular momenta if the mass ratio is rational.

The Bloch criterion aligns with the Landau criterion based on elementary excitations.

Higher angular momenta persistent currents are more stable than previously believed.

Abstract

In this paper we analyze the possibility of persistent currents of a two-species bosonic mixture in the one-dimensional ring geometry. We extend the arguments used by Bloch to obtain a criterion for the stability of persistent currents for the two-species system. If the mass ratio of the two species is a rational number, persistent currents can be stable at multiples of a certain total angular momenta. We show that the Bloch criterion can also be viewed as a Landau criterion involving the elementary excitations of the system. Our analysis reveals that persistent currents at higher angular momenta are more stable for the two-species system than previously thought.