Pairing and Phase Separation in a Polarized Fermi Gas
  We report the observation of a pairing in a number polarized two-component gas of atomic fermions. Beyond a critical polarization, the gas separates into a superfluid paired core surrounded by a shell of normal unpaired fermions. The critical polarization diminishes with decreasing attractive interaction. We also measure the parameter \beta = 0.54 (5) describing the universal energy of a strongly interacting Fermi gas, and find good agreement with most recent theory. These results are relevant to predictions of exotic new phases of quark matter and of strongly magnetized superconductors. 
Guthrie B. Partridge, Wenhui Li, Ramsey I. Kamar, Yean-an Liao,   Randall G. Hulet