Cavity QED of Strongly Correlated Electron Systems: A No-go Theorem for Photon Condensation
May 29th, 2019 MARCO POLINI Instituto Italiano di Tecnologia

Despite decades of work, it is still unclear whether an equilibrium superradiant quantum phase transition (which will be referred to as "photon condensation”) can occur or not in quantum many-body models of condensed matter relevance. In this talk, I will first show that gauge invariance forbids photon condensation when a non-relativistic quantum many-body system is coupled to a cavity field.

I will then present a microscopic theory of cavity quantum electrodynamics of an extended Falicov-Kimball model, showing that, in agreement with the general theorem, its insulating ferroelectric and exciton condensate phases are unaltered by the cavity.

Seminar, May 29, 2019, 12:00. ICFO’s Seminar Room

Hosted by Prof. Frank Koppens