Effect of condensate depletion on the critical velocity for vortex nucleation in quantum fluids

By performing numerical simulations of object motion through homogeneous dilute quantum fluids, we show that the critical velocity for vortex formation at constant average superfluid density depends on the condensate fraction. We Suggest that the lower critical velocity at lower condensate fraction is due to transitions between the no-vortex and vortex states driven by density fluctuations.