Cavity QED of the graphene cyclotron transition

Understand

We investigate theoretically the cavity quantum electrodynamics of the cyclotron transition for Dirac fermions in graphene.

• We show that the ultrastrong coupling regime characterized by a vacuum Rabi frequency comparable or even larger than the transition frequency can be obtained for high enough filling factors of the graphene Landau levels.
• Important qualitative differences occur with respect to the corresponding physics of massive electrons in a semiconductor quantum well.
• In particular, an instability for the ground state analogous to the one occuring in the Dicke-model is predicted for increasing value of the electron density.