We propose a physical mechanism which enables permanent Rabi oscillations in driven-dissipative condensates of exciton-polaritons in semiconductor microcavities subjected to external magnetic fields. The method is based on incoherent excitonic reserv
oir engineering. We demonstrate that permanent non-decaying oscillations may appear due to the parity-time (PT) symmetry of the coupled exciton-photon system realised in a specific regime of pumping to the exciton state and depletion of the reservoir. For effective non-zero exciton-photon detuning, permanent Rabi oscillations occur with unequal amplitudes of exciton and photon components. Our predictions pave way to realisation of integrated circuits based on exciton-polariton condensates.
The problem of photonic phase transition for the system of a two-level atomic ensemble interacting with a quantized single-mode electromagnetic field in the presence of optical collisions (OC) is considered. We have shown that for large and negative
atom-field detuning a photonic field exhibits high temperature second order phase transition to superradiant state under thermalization condition for coupled atom-light states. Such a transition can be connected with superfluid (coherent) properties of photon-like low branch (LB) polaritons. We discuss the application of metallic cylindrical waveguide for observing predicted effects.
We describe a new type of spatially periodic structure (lattice models): a polaritonic crystal (PolC) formed by a two-dimensional lattice of trapped two-level atoms interacting with quantised electromagnetic field in a cavity (or in a one-dimensional
array of tunnelling-coupled microcavities), which allows polaritons to be fully localised. Using a one-dimensional polaritonic crystal as an example, we analyse conditions for quantum degeneracy of a low-branch polariton gas and those for quantum optical information recording and storage.
