Kibble-Zurek mechanism in polariton graphene

We study the formation of topological defects (quantum vortices) during the formation of a 2D polariton condensate at the \Gammapoint of a honeycomb lattice via the Kibble-Zurek mechanism. The lattice modifies the single-particle dispersion. The typical interaction energies at the quench time correspond to the linear part of the dispersion. The resulting scaling exponent for the density of topological defects is numerically found as...