Driven-dissipative confined polariton condensate under magnetic field
  We investigate exciton-polariton condensation under magnetic field in a single high-quality semiconductor micropillar cavity. We observe successive polariton condensation of each spin component for two distinct threshold powers. Pronounced and non-monotonous variations of both the Zeeman splitting and the circular polarization of the emission are measured across these two condensation thresholds. This unexpected behavior deeply deviates from the so-called spin Meissner effect predicted for a fully thermalized system. Our measurements can be understood in a kinetic approach taking into account spin-anisotropic interactions within the entire system: the polariton condensate and the cloud of uncondensed excitons. 
C. Sturm, D. Solnyshkov, O. Krebs, A. Lema\^itre, I. Sagnes, E.   Galopin, A. Amo, G. Malpuech, and J. Bloch
cond-mat.mes-hall