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QI: Fachverband Quanteninformation

QI 21: Quantum Information: Concepts and Methods III

QI 21.1: Hauptvortrag

Freitag, 13. März 2026, 09:30–10:00, BEY/0245

Non-Hermitian topology and directional amplification — •Clara Wanjura — Max Planck Institute for the Science of Light, Staudtstraße 2, Erlangen

Topology has been a major research theme in condensed matter physics and is associated with a number of remarkable phenomena such as robust edge states. More recently, topology started to be investigated in systems experiencing gain and loss, sparking the field of non-Hermitian topology. However, for a long time, a clear observable signature of non-Hermitian topology had been lacking.

We recently closed this gap and showed that non-trivial, non-Hermitian topology is in one-to-one correspondence with the phenomenon of directional amplification in one-dimensional driven-dissipative systems, e.g., cavity arrays. Directional amplification allows to selectively amplify signals depending on their propagation direction and has attracted much attention as key resource for applications, such as quantum information processing. We experimentally demonstrated this connection between non-Hermitian topology and directional amplification in a cavity optomechanical system as well as realised a sensor based on non-Hermitian topology for which the sensitivity is exponentially enhanced with increasing system size.

Our work opens up new routes for the design of multimode robust directional amplifiers and novel topological sensors that can be integrated in scalable platforms such as superconducting circuits, cavity optomechanical systems, plasmonic waveguides and nanocavity arrays.

Keywords: Topology; Open Quantum Systems; Driven-Dissipative Systems; Directional Amplification