BEC–BCS-laser crossover in Coulomb-correlated electron–hole–photon systems

Abstract

Many-body features caused by Coulomb correlations are of great importance for understanding phenomena pertaining to polariton systems in semiconductor microcavities, i.e. electron–hole–photon systems. Remarkable many-body effects are shown to exist in both thermal-equilibrium phases and non-equilibrium lasing states. We then show a unified framework for connecting the thermal-equilibrium and the non-equilibrium steady states based on a non-equilibrium Green's function approach. Bose–Einstein condensate (BEC)–Bardeen–Cooper–Schrieffer (BCS)-laser crossovers are investigated by using this approach.