Figure 1
APS/Alan Stonebraker

Figure 1: In the experiment, a cloud of fermionic atoms is confined to two dimensions. Atoms with opposite spin bind into pairs through attractive interactions, and this pairing can produce a superfluid state. The strength of the binding is controlled by an applied magnetic field. For weak binding, the pair size is large (left), and the pressure is just the Fermi pressure. As the binding increases, the pair size shrinks (center), and the pressure drops. For strong binding, the atoms bind into bosonic molecules (right), and the pressure becomes that of a Bose gas.