Pairing of Electromagnetic Bosons under Spin-Orbit Coupling

We discuss pairing of excitons and polaritons under effective spin-orbit coupling in two-dimensional semi-conductors. The spin-orbit coupling is shown to induce dynamical broadening of a two-body bound state. Application of a transverse magnetic field yields the rich Feshbach resonance phenomenology. We predict quan-tum bosonic halos with a synthetic angular momentum Lz = +/- 2 h over line . The d-wave-like dressing of the nominally s-wave bound state is induced by spin-orbital coupling to the continuum in the open channel. As a possible manifestation of the phenomenon in the equilibrium phase diagram we predict biexcitonic Mott supercurrent: Dissociation of a biexciton Bose-Einstein condensate into a superfluid current of excitons upon increasing the density.