Spin current shot noise as a probe of interactions in mesoscopic systems

TL;DR

This paper demonstrates that spin-resolved current shot noise can effectively probe electron interactions in mesoscopic systems, revealing interaction types, correlations, and enabling measurement of spin relaxation times.

Contribution

It introduces the use of spin current shot noise as a novel tool to investigate interactions and correlations in mesoscopic systems, with practical measurement proposals.

Findings

Spin current noise is zero in normal-superconducting junctions.

Spin current noise is Poissonian in single electron transistors.

Interactions can induce weak attractive correlations far from equilibrium.

Abstract

It is shown that the spin resolved current shot noise can probe attractive or repulsive interactions in mesoscopic systems. This is illustrated in two physical situations : i) a normal-superconducting junction where the spin current noise is found to be zero, and ii) a single electron transistor (SET), where the spin current noise is found to be Poissonian. Repulsive interactions may also lead to weak attractive correlations (bunching of opposite spins) in conditions far from equilibrium. Spin current shot noise can be used to measure the spin relaxation time $T_1$, and a set-up is proposed in a quantum dot geometry.