Vortex Nucleation and Transition to Turbulence in two-component Bose—Einstein condensates

We theoretically study the instability of countersuperflow, i.e., two counter-propagating miscible superflows, in uniform two-component Bose-Einstein condensates. When the relative velocity of the counterflow exceeds a critical value, the instability causes the nucleation and expansion of vortex rings. A lot of vortex reconnections are caused and lead to binary quantum turbulence, where both components become turbulent. Then we introduce the unique velocity in two-component Bose-Einstein condensates and investigate the probability distribution of the velocity in the binary quantum turbulence to obtain the probability distribution whose tail in the high-velocity region is considerably suppressed compared to single-component quantum turbulence.