Colloquium by Professor Han PU (Rice University)

Quantum Rabi and Dicke models are two of the most iconic models in quantum optics, providing a full quantum description of atom-light interaction. In these models, the key focus is atom-photon coupling which give rise to the superradiance phase transition. In this talk, I will show how new physics arises when new ingredients are added to the model. In the first example, we will consider a generalized Rabi model in the presence of two-photon pumping and decay. In the second example, we will examine generalized Dicke models in the presence of various types of atom-atom interactions. We will show that the interplay between these new ingredients and the atom-photon coupling yields much richer phase diagrams and novel phase transitions.