Non-Hermitian Kibble-Zurek Mechanism with Tunable Complexity in Single-Photon Interferometry
Lei Xiao, Dengke Qu, Kunkun Wang, Hao-Wei Li, Jin-Yu Dai, Balázs Dóra, Markus Heyl, Roderich Moessner, Wei Yi, Peng Xue
Abstract
Non-Hermitian descriptions of quantum matter have seen impressive progress recently, with major advances in understanding central aspects such as their topological properties or the physics of exceptional points, the non-Hermitian counterpart of critical points. Here, we use single-photon interferometry to reconstruct the non-Hermitian Kibble-Zurek mechanism and its distinct scaling behavior for exceptional points, by simulating the defect production upon performing slow parameter ramps. We report progress along two axes. First, we realize parameter ramps across higher-order exceptional points, providing experimental access to their theoretically predicted characteristic Kibble-Zurek scaling behavior in the defect production. Second, we extend the scaling properties to the defect fluctuations, which enables us to extract the correlation length and dynamical exponents of the underlying the exceptional point (EP) and therefore to gain direct experimental information about the universality class of the EPs. Our work represents a step toward increasing the experimental complexity of non-Hermitian quantum time evolution, as part of the quest to move the frontier from single-particle physics toward increasingly complex settings.