Abundance of Weyl points in semiclassical multi-terminal superconducting nanostructures

TL;DR

This paper demonstrates that multi-terminal superconducting nanostructures host numerous Weyl points in their Andreev bound state spectrum, with potential for experimental detection and implications for topological quantum physics.

Contribution

It identifies and characterizes the abundance of Weyl points in the spectrum of multi-terminal superconducting nanostructures using random matrix theory and quantum circuit models.

Findings

High density of Weyl points in 4-terminal structures

Correlation patterns in 3D parameter space

Potential for experimental observation

Abstract

We show that the quasi-continuous gapless spectrum of Andreev bound states in multi-terminal semi-classical superconducting nanostructures exhibits a big number of topological singularities. We concentrate on Weyl points in a 4-terminal nanostructure, compute their density and correlations in 3D parameter space for a universal RMT model as well as for the concrete nanostructures described by the quantum circuit theory. We mention the opportunities for experimental observation of the effect in a quasi-continuous spectrum.