Rotating ground states of a one-dimensional spin-polarized gas of fermionic atoms with attractive p-wave interactions on a mesoscopic ring

TL;DR

This paper demonstrates that a one-dimensional spin-polarized fermionic gas with attractive p-wave interactions on a mesoscopic ring naturally exhibits two degenerate ground states with opposite rotations, due to quantum effects and topology.

Contribution

It reveals the spontaneous rotation phenomenon in a fermionic gas on a ring, highlighting the role of quantum statistics, topology, and exchange interactions in this behavior.

Findings

Degenerate pair of ground states with opposite rotation directions

Spontaneous rotation occurs without external bias

Quantum statistics and topology induce this effect

Abstract

The major finding of this paper is that a one-dimensional spin-polarized gas comprised of an even number of fermionic atoms interacting via attractive p-wave interactions and confined to a mesoscopic ring has a degenerate pair of ground states that are oppositely rotating. In any realization the gas will thus spontaneously rotate one way or the other in spite of the fact that there is no external rotation or bias fields. Our goal is to show that this counter-intuitive finding is a natural consequence of the combined effects of quantum statistics, ring topology, and exchange interactions.