Measuring topological invariants for higher-order exceptional points in quantum three-mode systems.

ABSTRACT: Owing to the presence of exceptional points (EPs), non-Hermitian (NH) systems can display intriguing topological phenomena without Hermitian analogs. However, experimental characterizations of exceptional topological invariants have been restricted to second-order EPs (EP2s) in classical or semiclassical systems. We here propose an NH multi-mode system with higher-order EPs, each of which is underlain by a multifold-degenerate multipartite entangled eigenstate. We implement the NH model by controllably coupling a Josephson-junction-based electronic mode to two microwave resonators. We experimentally quantify the topological invariant for an EP3, by mapping out the complex eigenspectra of the tripartite system along a loop surrounding this EP3 in the parameter space. The nonclassicality of

SUBMITTER: Han PR 

PROVIDER: S-EPMC11603074 | biostudies-literature | 2024 Nov

REPOSITORIES: biostudies-literature