Quantum-Dot Parity Effects in Trivial and Topological Josephson Junctions

TL;DR

This paper investigates how quantum-dot parity influences Josephson junctions, revealing differences between trivial and topological phases through conductance and current measurements in a hybrid interferometer.

Contribution

It demonstrates the impact of dot parity on phase behavior and conductance in topological versus trivial Josephson junctions using a full-shell hybrid interferometer.

Findings

Odd parity enhances zero-bias conductance in topological phase

Critical current is increased for odd parity in topological junctions

No phase flip occurs in topological junctions with coupled superconductors

Abstract

An odd-occupied quantum dot in a Josephson junction can flip transmission phase, creating a {\pi}-junction. When the junction couples topological superconductors, no phase flip is expected. We investigate this and related effects in a full-shell hybrid interferometer, using gate voltage to control dot-junction parity and axial magnetic flux to control the transition from trivial to topological superconductivity. Enhanced zero-bias conductance and critical current for odd parity in the topological phase reflects hybridization of the confined spin with zero-energy modes in the leads.