Seminarium Fizyki Materii Skondensowanej

I will describe our work related to the recent observations ofinstabilities of non-equilibrium exciton-polariton condensates. Withoutany free parameters, we find an excellent agreement between theexperimental data and numerical simulations of the open-dissipativeGross-Pitaevskii equation in the case of nonresonant excitation. Thebreakup of the condensate is due to the long-sought reservoir-induceddynamical instability. In the case of resonant excitation, we observed thereal-space collapse of the polariton fluid explained by the effectiveattractive interactions mediated by the lattice phonons.