Shot noise in charge and magnetization currents of a quantum ring

TL;DR

This paper investigates shot noise in a quantum ring with electron interactions, revealing distinct noise behaviors in charge and magnetization currents and their dependence on interactions and population states.

Contribution

It identifies two different noise correlation regimes in a quantum ring and analyzes their dependence on electron interactions and population inversion.

Findings

Charge current noise can be super-Poissonian due to interactions.

Magnetization current noise is less affected by interactions.

Population inversion can greatly enhance magnetization current noise.

Abstract

The shot noise in a quantum ring, connected to leads, is studied in the presence of electron interactions in the sequential tunneling regime. Two qualitatively different noise correlations with distinctly different behaviors are identified and studied in a large range of parameters. Noise in the total current is due to the discreteness of the electron charge and can become super-Poissonian as result of electron interaction. The noise in the magnetization current is comparatively insensitive to the interaction but can be greatly enhanced if population inversion of the angular states is assumed. The characteristic time scales are studied by a Monte-Carlo simulation.