Spontaneous polariton currents in periodic lateral chains
  We predict spontaneous generation of superfluid polariton currents in planar microcavities with lateral periodic modulation of both potential and decay rate. A spontaneous breaking of spatial inversion symmetry of a polariton condensate emerges at a critical pumping, and the current direction is stochastically chosen. We analyse the stability of the current with respect to the fluctuations of the condensate. A peculiar spatial current domain structure emerges, where the current direction is switched at the domain walls, and the characteristic domain size and lifetime scale with the pumping power. 
A. V. Nalitov, T. C. H. Liew, A. V. Kavokin, B. L. Altshuler, and Y.   G. Rubo
cond-mat.mes-hall