Magnetic Flux Response of Non-Hermitian Topological Phases

TL;DR

This paper explores how non-Hermitian topological phases respond to magnetic flux, revealing phenomena like flux skin effects, spectral jumps, and Majorana modes, with implications for experimental realization.

Contribution

It identifies and characterizes the flux response phenomena in non-Hermitian topological phases, linking symmetry classes to specific flux effects and providing a comprehensive theoretical framework.

Findings

Flux skin effect localizes in-gap modes at flux cores

Existence of flux spectral jump at specific momentum

Discovery of flux Majorana modes in non-Hermitian systems

Abstract

We derive the response of non-Hermitian topological phases with intrinsic point gap topology to localized magnetic flux insertions. In two spatial dimensions, we identify the necessary and sufficient conditions for a flux skin effect that localizes an extensive number of in-gap modes at a flux core. In three dimensions, we furthermore establish the existence of: a flux spectral jump, where flux tube insertion fills up the entire point gap only at a single parallel crystal momentum; a higher-order flux skin effect, which occurs at the ends of flux tubes in presence of pseudo-inversion symmetry; and a flux Majorana mode that represents a spectrally isolated mid-gap state in the complex energy plane. We uniquely associate each non-Hermitian symmetry class with intrinsic point gap topology with one of these cases or a trivial flux response, and discuss possible experimental realizations.