Quantum critical behavior in driven and strongly interacting Rydberg gases
Prof. Dr. Hans Peter Büchler (Universität Stuttgart)

We study the appearance of correlated many-body phenomena in an ensemble of atoms driven resonantly into a strongly interacting Rydberg state. The ground state of the Hamiltonian describing the driven system exhibits a second order quantum phase transition. We derive the critical theory for the quantum phase transition and show that it describes the properties of the driven Rydberg system in the saturated regime. We find that the suppression of Rydberg excitations known as blockade phenomena exhibits an algebraic scaling law with a universal exponent. Special focus is on the system in one dimension in the presence of an underlying lattice structure, where we will show that in the driven system a two-stage melting takes place from a commensurate solid into a floating solid phase and finally into a paramagnetic phase.