Persistent Current of SU(N) Fermions

TL;DR

This paper investigates how SU(N) fermions in a ring with interactions and flux exhibit unique persistent current behaviors, including fractional flux quantum sharing and spinon creation, with implications for universality and finite size effects.

Contribution

It introduces a combined Bethe ansatz and numerical approach to reveal spinon creation and flux quantum evolution in SU(N) fermions, highlighting new universal and finite size phenomena.

Findings

Persistent current evolves from single particle to fractional flux quantum.

Spinon creation occurs in the ground state due to interactions and flux.

Persistent current is suppressed at integer fillings by the Mott gap.

Abstract

We study the persistent current in a system of SU($N$) fermions with repulsive interaction confined in a ring-shaped potential and pierced by an effective magnetic flux. By applying a combination of Bethe ansatz and numerical analysis, we demonstrate that, as a combined effect of spin correlations, interactions and applied flux a specific phenomenon can occur in the system: spinon creation in the ground state. As a consequence, peculiar features in the persistent current arise. The elementary flux quantum, which fixes the persistent current periodicity, is observed to evolve from a single particle one to an extreme case of fractional flux quantum, in which one quantum is shared by all the particles. We show that the persistent current depends on the number of spin components $N$, number of particles and interaction in a specific way that in certain physical regimes has universality traits. At integer filling fractions, the persistent current is suppressed above a threshold of the repulsive interaction by the Mott spectral gap. Despite its mesoscopic nature, the current displays a clear finite size scaling behavior. Specific parity effects in the persistent current landscape hold.