Onsager vortex formation in two-component Bose–Einstein condensates

We numerically study the dynamics of quantized vortices in two-dimensional two-component Bose–Einstein condensates (BECs) trapped by a box potential. For one-component BECs in a box potential, it is known that quantized vortices form Onsager vortices, which are clusters of same-sign vortices. We confirm that the vortices of the two components spatially separate from each other—even for miscible two-component BECs—suppressing the formation of Onsager vortices. This phenomenon is caused by the repulsive interaction between vortices belonging to different components, hence, suggesting a new possibility for vortex phase separation. (author)