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arXiv · 2507.02038

Topological Reality Switch: Towards Bulk-Boundary Selective Lasing

Sayed Ali Akbar Ghorashi·Masatoshi Sato
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Abstract

The emergence of complex spectra in non-Hermitian systems causes dramatic changes even under weak perturbations, significantly hindering their precise control for study and integration into practical applications. Achieving a controlled method to generate a real spectrum in non-Hermitian systems has long been a key objective in the field. In this study, we explore the 2D non-Hermitian Su-Schrieffer-Heeger (SSH) model and introduce a reality switch that allows for the controllable induction of a real spectrum depending on the imposed boundary condition. We show that a topological phase transition in the complex gap accompanies the switching process. Our work lays the cornerstone for developing a selective bulk-boundary control mechanism for the gain and lasing behaviors in non-Hermitian systems.

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Sayed Ali Akbar Ghorashi, Masatoshi Sato. 2025-07-02. Topological Reality Switch: Towards Bulk-Boundary Selective Lasing. https://arxiv.org/abs/2507.02038

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