The Bose-Einstein Condensate- a Superfluid Gas of Coherent Atoms

Following the theoretical suggestion [2], we have demonstrated a new method to create vortices in Bose-Einstein condensates. Vortices were imprinted into the condensate wavefunction using topological phases. Sodium condensates held in an Ioffe-Pritchard magnetic trap were transformed from a non-rotating state to one with quantized circulation by adiabatically inverting the magnetic bias field along the trap axis [3]. During this process, the magnetic fields rotated around position-dependent axes, and the associated Berry’s phase resulted in a vortex singularity. Using surface wave spectroscopy, the axial angular momentum per particle of the vortex states was found to be consistent with 2 or 4 , depending on the hyperfine state of the condensate.