Quantum criticality in driven open quantum lattices
Driven open quantum systems with engineered reservoirs are attracting considerable interest for the generation of targeted quantum states and for the manipulation of quantum information. For example, engineered two-photon driving and two-photon losses on a photonic cavity can confine the state of the photon mode to the quantum manifold spanned by two coherent states of opposite phases, which can be used as a logical qubit and, in particular, for the generation of Schroedinger cat states with even or odd parity. Assembling together a number of such elementary systems in a lattice configuration produces open quantum materials, providing a platform for open-state quantum simulation. In this talk, after a general introduction, we will discuss recently developed theoretical methods to predict the steady-state of open quantum lattices in a regime with moderate entropy. We will show results describing the emergence of quantum criticality in a lattice of coupled photonic cavities with two-photon driving and dissipation.