“Superradiant” phase transition in the presence of optical collisions

A problem of high-temperature phase transitions for coupled (dressed) atom-light states and polaritons is considered. An achievement of thermodynamically equilibrium phase for such a states is possible under interaction between rubidium atoms and quantum irradiation in the presence of optical collisions (OCs) with ultra-high pressure buffer gas particles being under high temperatures (up to 530 K). Special metallic micro-waveguides permitting photon trapping are proposed for purpose of the enhancement of atom-field interaction. A photonic phase transition to the superradiant state, determined by the equilibrium state of coupled system, was theoretically predicted. It have been shown that under large negative atom-light detunings and certain waveguide parameters photon-like low branch (LB) polaritons undergo high-temperature phase transition to condensate (superfluid) state.