Vortex quantum creation and winding number scaling in a quenched spinor   Bose gas
  Motivated by a recent experiment, we study non-equilibrium quantum phenomena taking place in the quench of a spinor Bose-Einstein condensate through the zero-temperature phase transition separating the polar paramagnetic and planar ferromagnetic phases. We derive the typical spin domain structure (correlations of the effective magnetization) created by the quench arising due to spin-mode quantum fluctuations, and establish a sample-size scaling law for the creation of spin vortices, which are topological defects in the transverse magnetization. 
Michael Uhlmann, Ralf Sch\"utzhold and Uwe R. Fischer