FIGURE 1. Cool rotations.

Vortex structures observed in rotating superfluids by Zwierlein et al.³. a, A Bose−Einstein condensate (BEC) of bosonic (integer spin) sodium atoms. b, A BEC formed of two fermionic (half-integer spin) ⁶Li atoms bound together tightly to form a gas of bosonic molecules. c, A Fermi gas of loosely bound pairs of ⁶Li atoms in the strongly interacting regime, the first unambiguous sign of superfluidity seen in a fermionic gas.