The systems on which we focus are hybrid light-matter setups involving a macroscopic number of neutral polarizable atoms strongly interacting with electromagnetic fields. The high degree of control on the atom trapping and cooling as well as on the boundary conditions for the field allows access to regimes where quantum fluctuations of both subsystems are important and their timescales are such that one is forced to treat matter and light on equal footing. Such peculiar quantum plasmas, currently realized in the lab using for instance nanophotonic devices and Fabry-Perot resonators, show a wealth of new phenomena of both fundamental and technological interest at the boundary between condensed matter physics and quantum optics.
We are interested in many-body phenomena such as non-equilibrium phase transitions and collective dynamics emergent in these systems, where the unusual combination of peculiar long-range retarded interactions with the driven-dissipative nature could violate so far known paradigms. Our approach combines expertise in condensed matter physics, non-equilibrium physics of open systems, as well as quantum optics. In particular, we mainly employ non-equilibrium quantum-field-theoretical methods, providing the required flexibility to treat the macroscopic properties of quantum many-body open systems.
The strong long-range interactions intrinsic to these hybrid atom-photon systems can induce spontaneous crystallization phenomena, with additional peculiarities arising from the driven-dissipative nature.
The strong long-range interactions combined with drive and dissipation can give rise to non-equilibrium steady-states, novel dynamical phase transitions, as well as peculiar quench dynamics.
The light field strongly coupled to the neutral atoms can work as an artificial dynamical gauge field for the matter, giving rise for instance to exotic topological states.