Non-Hermitian edge burst without skin localizations

TL;DR

This paper investigates the phenomenon of edge burst in non-Hermitian quantum walks, demonstrating its occurrence without skin localization and exploring conditions affecting its appearance, thus broadening potential applications.

Contribution

It reveals that edge burst can occur independently of skin localization and identifies spectral conditions necessary for its emergence, expanding understanding of non-Hermitian effects.

Findings

Edge burst occurs without skin localization in certain non-Hermitian lattices.

The presence of edge burst depends on the imaginary gaplessness of the spectrum.

Removing skin localization restrictions broadens potential applications.

Abstract

In a class of non-Hermitian quantum walk in lossy lattices with open boundary conditions, an unexpected peak in the distribution of the decay probabilities appears at the edge, dubbed edge burst. It is proposed that the edge burst is originated jointly from the non-Hermitian skin effect (NHSE) and the imaginary gaplessness of the spectrum [Wen-Tan Xue et al., Phys. Rev. Lett. 128, 120401 (2022)]. Using a particular one-dimensional lossy lattice with a nonuniform loss rate, we show that the edge burst can occur even in the absence of skin localization. Furthermore, we discuss that the edge burst may not appear if the spectrum satisfies the imaginary gaplesness condition. Aside from its fundamental importance, by removing the restrictions on observing the edge burst effect, our results open the door to broader design space for future applications of the edge burst effect.