Circuit theory for noise in incoherent normal-superconducting dot structures

TL;DR

This paper develops a circuit theory framework to analyze noise and current fluctuations in mesoscopic normal-superconducting structures, simplifying calculations under weak proximity effects and aligning with semiclassical principles.

Contribution

It introduces simplified equations for current fluctuations in complex mesoscopic circuits with normal and superconducting terminals, extending the theory to multi-dot systems.

Findings

Derived simplified equations for second-order current correlators.

Confirmed the consistency with the semiclassical principle of minimal correlations.

Extended the theory to multi-dot configurations.

Abstract

We consider the current fluctuations in a mesoscopic circuit consisting of nodes connected by arbitrary connectors, in a setup with multiple normal or superconducting terminals. In the limit of weak superconducting proximity effect, simplified equations for the second-order cross-correlators can be derived from the general counting field theory, and the result coincides with the semiclassical principle of minimal correlations. We discuss the derivation of this result in a multi-dot case.