We generalize the spin Meissner effect for an exciton-polariton condensate confined in annular geometries to the case of nontrivial topology of the condensate wave function. In contrast to the conventional spin Meissner state, topological spin Meissner states can in principle be observed at arbitrary high magnetic fields not limited by the critical magnetic field value for the condensate in a simply connected geometry. One special example of the topological Meissner states are half-vortices. We show that in the absence of magnetic field, half-vortices in a ring exist in a form of a superposition of elementary half-vortex states, which resolves recent experimental results where such puzzling superposition was observed. Furthermore, we show that if a pure half-vortex state is to be observed, a nonzero magnetic field of a specific magnitude needs to be applied. Studying exciton polaritons in a ring in the presence of TE-TM splitting, we observe spin Meissner states that break the rotational symmetry of the system by developing inhomogeneous density distributions. We classify various states arising in the presence of nonzero TE-TM splitting based on what states they can be continued from by increasing the TE-TM splitting parameter from zero. With further increasing TE-TM splitting, states with broken symmetry may transform into stable half-dark solitons and therefore may serve as a useful tool to generate various nontrivial states of a spinor condensate.

• Received 10 May 2016
• Revised 11 August 2016

DOI:https://doi.org/10.1103/PhysRevB.94.115407