---

Developments in quantum optics and quantum engineering have brought forth the possibility of studying emergent collective phenomena in hybrid quantum light-matter systems. These platforms, which are intrinsically driven and dissipative, allow to probe fundamental many body physics in uncharted territories. In this talk I will discuss the steady state properties of paradigmatic lattice models of photons coupled to qubits, highlighting those aspects of the physics which are genuine nonequilibrium features and cannot be understood even qualitatively from an effective equilibrium. I will then discuss the role of non-Markovian bath correlations on a prototypical light-matter phase transition, the Dicke superradiance of N qubits coupled to a cavity, and show that ohmic/subohmic environemnts can induce a dissipative phase transition surving even at finite N, smoothly connected to the well studied Caldeira-Leggett/spin-boson one. Finally, I will present our ongoing effort to develop a new approach to driven-dissipative lattice models, based on non-equilibrium dynamical mean field theory.

---

Marco Schiro
Seminar room of the Institute of Physics II
Contact: Jamir Marino