Programme

O.8 -- Oral, ANSWCCMS-2023

Date: Friday, 10 November 2023

Time: 14:30 - 15:00

Collective non-Hermitian skin effect of non-reciprocal many-body systems

Beom Hyun Kim

Center for Theoretical Physics of Complex Systems, Institute for Basic Science, Daejeon, Korea

In open quantum systems, a rich variety of exotic topological phases of matter, that has no Hermitian counterpart, has emerged. Non-Hermitian spin effect (NHSE), the exponential localization of all eigenstates at a specific boundary, is one of intriguing non-Hermitian phenomena. The NHSE is a manifestation of non-Hermitian topology characterized by the complex eigenspectrum. The Hatano-Nelson model is a one-dimensional Hamiltonian featuring non-reciprocal hopping terms. This model provides the prototypical behaviors for the NHSE phenomena. Recently, significant attention has been directed towards understanding how the NHSE behaves in the present of many-body interactions. In this study, we investigated the NHSE of the many-body fermion systems by utilizing the half-filled interacting Hatano-Nelson model of spin-half fermions. We discovered that the strong interactions lead to the absence of the NHSE in the ground state but excited states with the doubloon-holon pairs, as well-defined collective excitations, show the many-body NHSE even in strong interacting limit. Furthermore, we established this collective NHSE by illustrating the bulk-boundary correspondence mediated by the point-gap topology in the many-body eigenspectrum.

Presenter: Beom Hyun Kim