When graphene is placed inside a chiral cavity –one whose vacuum fluctuations are circularly polarized, such as a recent one fabricated in Kono Lab– the interaction between electrons and the quantized cavity field alters the topology of the bands. In our recent work, we show that this interaction gives rise to unidirectional edge states that are of hybrid nature composed of an electron and a photon. These glowing edges carry current in only one direction and can be switched on by tuning the cavity field, without any external drive or magnetic field. The result demonstrates that chiral vacuum fluctuations alone can create and control topological edge channels in graphene, connecting cavity quantum electrodynamics with topological condensed-matter physics. 

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In this ArXiv preprint 2504.03842, we demonstrate a subtle competition between cavity frequency and interlayer tunneling in graphene stacks that is responsible for topological phase transitions in light-matter Hilbert space and that cannot be captured by mean-field theory in vacuum. A systematic exploration of multilayer graphene heterostructures and stacking configurations in a chiral tHz cavity reveals that linear dispersion enhances the low-energy cavity-induced topological gap.