Speaker
Description
We investigate how quantum fluctuations in cavities can modify the topological properties of materials such as graphene and quantum Hall (QH) systems. First, building on recent theoretical and experimental advances, we analyze the coupling between QH states and cavity modes with both linear and circular polarizations. Using a combination of microscopic and hydrodynamic approaches, we demonstrate that while the quantized Hall conductivity remains robust in topological limits, cavity coupling induces second-order quantum reactance corrections to the AC conductivities and shifts the Kohn mode frequency. Our methods apply broadly to both integer and fractional QH liquids. These results deepen our understanding of the interplay between QH states and cavity quantum fluctuations, with important implications for future research on topological quantum fluids and cavity-induced effect. In parallel, we propose a cavity-based scheme for realizing Haldane model by embedding graphene in a chiral cavity with time-reversal-symmetry breaking. This configuration enables equilibrium valley polarization and leads to photon–valley locking, manifested as an imbalance in cavity photon numbers associated with the valley degrees of freedom. We further show that topological phase transitions by sublattice split can be identified through sign changes in the valley photon number during interband excitations. These findings underscore the remarkable potential of utilizing cavity quantum fluctuations to engineer electronic and photonic properties specific to valleys and topologies, particularly within the realm of strong light-matter coupling.
