Critical velocity for vortex nucleation in a finite-temperature Bose gas
G. W. Stagg, R. W. Pattinson, C. F. Barenghi +1 more
We use classical field simulations of the homogeneous Bose gas to study the breakdown of superflow due to vortex nucleation past a cylindrical obstacle at finite temperature. Thermal fluctuations modify the vortex nucleation from the obstacle, turning antiparallel vortex lines (which would be nucleated at zero temperature) into wiggly lines, vortex rings, and even vortex tangles. We find that the critical velocity for vortex nucleation decreases with increasing temperature and scales with the speed of sound of the condensate, becoming zero at the critical temperature for condensation.
arXiv:1510.01895•Physical Review A•Feb 24, 2016•14 citations