Non-hermitian topology in multiterminal superconducting junctions

TL;DR

This paper explores non-hermitian topological phases in multiterminal superconducting junctions, revealing how engineered dissipation and symmetries lead to novel topological states with potential applications in quantum technologies.

Contribution

It introduces the concept of non-hermitian topology in multiterminal Josephson junctions and predicts new fragile and stable topological phases arising from system symmetries.

Findings

Identification of non-hermitian topological phases in superconducting systems

Prediction of fragile and stable topological states based on system symmetries

Analysis of exceptional points in multiterminal Josephson junctions

Abstract

Recent experimental advancements in dissipation control have yielded significant insights into non-hermitian Hamiltonians for open quantum systems. Of particular interest are the topological characteristics exhibited by these non-hermitian systems, that arise from exceptional points - distinct degeneracies unique to such systems. In this study, we focus on Andreev bound states in multiterminal Josephson junctions with non-hermiticity induced by normal metal or ferromagnetic leads. By investigating several systems of different synthetic dimensions and symmetries, we predict fragile and stable non-hermitian topological phases in these engineered superconducting systems.