Fourth-order exceptional points in correlated quantum many-body systems

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Contributors

Abstract

Non-Hermtian (NH) Hamiltonians effectively describing the physics of dissipative systems have become an important tool with applications ranging from classical metamaterials to quantum many-body systems. Exceptional points, the NH counterpart of spectral degeneracies, are among the paramount phenomena unique to the NH realm. While realizations of second-order exceptional points have been reported in a variety of microscopic models, higher-order ones have largely remained elusive in the many-body context, as they in general require fine tuning in high-dimensional parameter spaces. Here, we propose a microscopic model of correlated fermions in three spatial dimensions and demonstrate the occurrence of interaction-induced fourth-order exceptional points that are protected by chiral symmetry. We demonstrate their stability against symmetry-breaking perturbations and investigate their characteristic analytical and topological properties.

Details

Original languageEnglish
Article numberL121109
JournalPhysical Review B
Volume104
Issue number12
Publication statusPublished - 15 Sept 2021
Peer-reviewedYes