Generation of high-winding-number superfluid circulation in Bose-Einstein condensates

We experimentally and numerically demonstrate a method to generate multiply quantized superfluid circulation about an obstacle in highly oblate Bose-Einstein condensates (BECs). We experimentally achieve pinned superflow with winding numbers as high as 11, which persists for at least 4 s. Our method conceptually involves spiraling a blue-detuned laser beam, around and towards the center of the BEC, and is experimentally implemented by moving the BEC in a spiral trajectory around a stationary laser beam. This optical potential serves first as a repulsive stirrer to initiate superflow, and then as a pinning potential to transport the superfluid circulation within the BEC. The spiral technique can be used either to generate a high-winding-number persistent current, or for controlled placement of a cluster of singly quantized vortices of the same circulation. Thus, the technique may serve as a building block in experimental architectures to create on-demand vortex distributions in BECs.

Automated summary

We demonstrate a method to generate multiply quantized superfluid circulation in highly oblate Bose-Einstein condensates (BECs) through experimental and numerical approaches. By spiraling a blue-detuned laser beam around and towards the center of the BEC, we are able to achieve pinned superflow with high winding numbers. This method can be used to generate persistent currents or control the placement of clusters of singly quantized vortices with the same circulation.