Non-Hermitian Josephson junctions with four Majorana zero modes

Fuente: arXiv
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Autores principales: Cayao, Jorge, Sato, Masatoshi
Formato: Preprint
Publicado: 2025
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author Cayao, Jorge
Sato, Masatoshi
author_facet Cayao, Jorge
Sato, Masatoshi
contents Josephson junctions formed by finite-length topological superconductors host four Majorana zero modes when the phase difference between the superconductors is $φ=π$ and their length is larger than the Majorana localization length. While this picture is understood in terms of a Hermitian description of isolated junctions, unavoidable transport conditions due to coupling to reservoirs make them open and ground for non-Hermitian effects that still remain largely unexplored. In this work, we investigate the impact of non-Hermiticity on Josephson junctions hosting four Majorana zero modes when they are coupled to normal leads. We demonstrate that, depending on whether inner or outer Majorana zero modes are subjected to non-Hermiticity, Andreev exceptional points can form between lowest (higher energy) Andreev bound states connected by stable zero real energy lines. We further find that the Andreev exceptional points give rise to strong local and nonlocal spectral weights, thus providing a way for their identification via, e.g., conductance measurements. Our findings unveil non-Hermiticity for designing non-Hermitian topological phases and for operating Andreev bound states in Josephson junctions hosting Majorana zero modes.
format Preprint
id arxiv_https___arxiv_org_abs_2508_19433
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Non-Hermitian Josephson junctions with four Majorana zero modes
Cayao, Jorge
Sato, Masatoshi
Superconductivity
Mesoscale and Nanoscale Physics
Josephson junctions formed by finite-length topological superconductors host four Majorana zero modes when the phase difference between the superconductors is $φ=π$ and their length is larger than the Majorana localization length. While this picture is understood in terms of a Hermitian description of isolated junctions, unavoidable transport conditions due to coupling to reservoirs make them open and ground for non-Hermitian effects that still remain largely unexplored. In this work, we investigate the impact of non-Hermiticity on Josephson junctions hosting four Majorana zero modes when they are coupled to normal leads. We demonstrate that, depending on whether inner or outer Majorana zero modes are subjected to non-Hermiticity, Andreev exceptional points can form between lowest (higher energy) Andreev bound states connected by stable zero real energy lines. We further find that the Andreev exceptional points give rise to strong local and nonlocal spectral weights, thus providing a way for their identification via, e.g., conductance measurements. Our findings unveil non-Hermiticity for designing non-Hermitian topological phases and for operating Andreev bound states in Josephson junctions hosting Majorana zero modes.
title Non-Hermitian Josephson junctions with four Majorana zero modes
topic Superconductivity
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2508.19433