Thermal remixing of phase-separated states in two-component bosonic condensates

Abstract

Weconsider a two-component interacting bosonic condensate with dominating intra-species repulsive density–density interactions.Westudy the phase diagram of the system at finite temperature with rotation, using large-scale Monte Carlo simulations of a two-component Ginzburg–Landau model of the system. In the presence of rotation, the system features a competition between longrange vortex–vortex interactions and short-range density–density interactions. This leads to a rotation-driven ‘mixing’ phase transition in a spatially inhomogeneous statewith a broken U(1) symmetry. Thermal fluctuations in this state lead to nematic two-component sheets of vortex liquids. At sufficiently strong inter-component interaction, we find that the superfluid and Z2 phase transitions split. This results in the formation of an intermediate state which breaks only Z2 symmetry. It represents two phase separated normal fluids with a difference in their densities.