Crossovers between superconducting symmetry classes

Abstract

We study the average density of states in a small metallic grain coupled to two superconductors with the phase difference $\pi$, in a magnetic field. The spectrum of the low-energy excitations in the grain is described by the random matrix theory whose symmetry depends on the magnetic field strength and coupling to the superconductors. In the limiting cases, a pure superconducting symmetry class is realized. For intermediate magnetic fields or couplings to the superconductors, the system experiences a crossover between different symmetry classes. With the help of the supersymmetric sigma-model we derive the exact expressions for the average density of states in the crossovers between the symmetry classes A-C and CI-C.

6 pages

References in corpus (2)

• Full counting statistics of electron transfer between superconductors
• Density of States below the Thouless Gap in a Mesoscopic SNS Junction

Cited by in corpus (3)

• Majorana state on the surface of a disordered 3D topological insulator
• Superconducting proximity effect in quantum wires without time-reversal symmetry
• Making s-wave superconductors topological with magnetic field