Transport moments and Andreev billiards with tunnel barriers

TL;DR

This paper develops a semiclassical approach to compute transport moments, reflection eigenvalues, and density of states in open chaotic systems with tunnel barriers, extending theoretical understanding beyond random matrix theory.

Contribution

It introduces a recursive semiclassical diagrammatic method incorporating tunnel barriers, providing new expressions for transport moments and density of states in complex quantum systems.

Findings

Derived the moment generating function of transmission eigenvalues at leading and subleading order.

Obtained the moment generating function of reflection eigenvalues and Wigner delay times.

Calculated the density of states of Andreev billiards with tunnel barriers.

Abstract

Open chaotic systems are expected to possess universal transport statistics and recently there have been many advances in understanding and obtaining expressions for their transport moments. However when tunnel barriers are added, which represents the situation in more general experimental physical systems much less is known about the behaviour of the moments. By incorporating tunnel barriers in the recursive semiclassical diagrammatic approach we obtain the moment generating function of the transmission eigenvalues at leading and subleading order. For reflection quantities quantum mechanical tunneling phases play an essential role and we introduce new structures to deal with them. This allows us to obtain the moment generating function of the reflection eigenvalues and the Wigner delay times at leading order. Our semiclassical results are in complementary regimes to the leading order results derived from random matrix theory expanding the range of theoretically known moments. As a further application we derive to leading order the density of states of Andreev billiards coupled to a superconductor through tunnel barriers.