1301.5133 (F. Ancilotto et al.)

Critical velocity, vortex shedding and drag in a unitary Fermi
superfluid    [PDF]

F. Ancilotto, L. Salasnich, F. Toigo

We study the real-time motion of a microscopic object in a cold Fermi gas at unitary conditions by using an extended Thomas-Fermi density functional approach. We find that spontaneous creation of singly quantized vortex-antivortex pairs occurs as a critical velocity is exceeded, which leads to a drag between the moving object and the Fermi gas. The resulting force is linear in the velocity for subsonic motion and becomes quadratic for supersonic motion.

View original: http://arxiv.org/abs/1301.5133