title: Fermionic superfluidity with imbalanced spin populations.
abstract: We established superfluidity in a two-state mixture of ultracold fermionic atoms with imbalanced state populations. This study relates to the long-standing debate about the nature of the superfluid state in Fermi systems. Indicators for superfluidity were condensates of fermion pairs and vortices in rotating clouds. For strong interactions, near a Feshbach resonance, superfluidity was observed for a broad range of population imbalances. We mapped out the superfluid regime as a function of interaction strength and population imbalance and characterized the quantum phase transition to the normal state, known as the Pauli limit of superfluidity.
authors.affiliation: Department of Physics, Massachusetts Institute of Technology (MIT)-Harvard Center for Ultracold Atoms, and Research Laboratory of Electronics, MIT, Cambridge, MA 02139, USA. zwierlei@mit.edu
authors.forename: Martin W
authors.initials: MW
authors.lastname: Zwierlein
authors.forename: André
authors.initials: A
authors.lastname: Schirotzek
authors.forename: Christian H
authors.initials: CH
authors.lastname: Schunck
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Ketterle