Fate of exceptional points under interactions: Reduction of topological classifications

Abstract

Despite recent extensive studies of the non-Hermitian topology, understanding interaction effects is left as a crucial question. In this paper, we address interaction effects on exceptional points which are protected by the non-trivial point-gap topology unique to non-Hermitian systems. Our analysis in a two-dimensional parameter space elucidates the existence of exceptional points and symmetry-protected exceptional rings fragile against interactions; they are topologically protected only in non-interacting cases. This fragility of exceptional points and symmetry-protected exceptional rings arises from the reduction of non-Hermitian topological classifications, which is elucidated by introducing topological invariants of the second-quantized Hamiltonian for both non-interacting and interacting cases. These topological invariants are also available to analyze the reduction phenomena of gapped systems. The above results strongly suggest similar reduction phenomena of exceptional points in generic cases and open up a new direction of research in the non-Hermitian topology.

14 pages, 12 figures, published in PRB

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Cited by in corpus (12)

• Non-Hermitian Topological Phases: Principles and Prospects
• Non-Hermitian Mott Skin Effect
• Proposal for Observing Yang-Lee Criticality in Rydberg Atomic Arrays
• Interaction-induced Liouvillian skin effect in a fermionic chain with a two-body loss
• Entanglement dynamics in the many-body Hatano-Nelson model
• Phase transitions and bunching of correlated particles in a non-Hermitian quasicrystal
• Spectral structure and doublon dissociation in the two-particle non-Hermitian Hubbard model
• Non-Hermitian Haldane-Hubbard model: Effective description of one- and two-body dissipation
• Emergent Topology in Many-Body Dissipative Quantum Matter
• Bulk-boundary correspondence in topological systems with the momentum dependent energy shift
• Non-Hermitian chiral anomalies in interacting systems
• Non-Hermitian topological superconductivity with symmetry-enriched spectral and eigenstate features