Bonn 2025 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 3: Photonics I
Q 3.4: Vortrag
Montag, 10. März 2025, 12:00–12:15, HS Botanik
Non-Hermitian geometry and topology induce non-trivial wave packet dynamics — •Ismaël Septembre1,2, Zhaoyang Zhang3, Pavel Kokhanchik2, Guillaume Malpuech2, and Dmitry Solnyshkov2,4 — 1University of Siegen, Germany — 2Institut Pascal, Clermont-Ferrand, France — 3Xi'an Jiaotong University, China — 4Institut Universitaire de France, Paris, France
The geometry of quantum states provides a solid framework for explaining complex phenomena that conventional approaches fail to address. Despite its success in Hermitian systems, quantum geometry remains far less understood in non-Hermitian systems.
In this presentation, I want to show new interesting effects that we predicted and observed experimentally recently using Rubidium vapor cells. First, we study a photonic quasicrystal and demonstrate that combined with non-Hermiticity, it leads to the delocalisation of the wave packet [PRL 132, 263801 (2024)]. This is rather counter-intuitive as both effects (quasicrystal and non-Hermiticity) usually lead to localisation. Then, I will show our latest work where a photonic crystal hosting a ring of exceptional points leads to an anomalous non-Hermitian drift, analogous to but different from the anomalous Hall drift of Hermitian systems [arXiv:2410.14428]. To describe this effect, the biorthogonal quantum metric must be used, which proves the utility of this approach.
Our works represent cutting-edge developments in the field of topological photonics in the broad sense and show how non-Hermiticity can lead to new effects with potential applications in beam steering.
Keywords: Topological photonics; Quantum geometry; Non-Hermitian physics; Exceptional points; Wave packet dynamics