Semiclassical theory of current correlations in chaotic dot-superconductor systems

TL;DR

This paper develops a semiclassical framework to analyze current correlations in chaotic dot-superconductor systems, showing positive cross correlations can occur without the proximity effect, aligning with quantum Green's function results.

Contribution

It introduces a semiclassical theory for current correlations in chaotic dot-superconductor systems, valid when the proximity effect is absent, and demonstrates its equivalence to quantum approaches.

Findings

Positive cross correlations occur with nonperfect interfaces.

Semiclassical approach matches quantum Green's function results.

Proximity effect is not necessary for positive correlations.

Abstract

We present a semiclassical theory of current correlations in multiterminal chaotic dot-superconductor junctions, valid in the absence of the proximity effect in the dot. For a dominating coupling of the dot to the normal terminals and a nonperfect dot-superconductor interface, positive cross correlations are found between currents in the normal terminals. This demonstrates that positive cross correlations can be described within a semiclassical approach. We show that the semiclassical approach is equivalent to a quantum mechanical Green's function approach with suppressed proximity effect in the dot.