Superfluidity without Condensation

The connection between superfluidity and Bose-Einstein condensation (BEC) is well studied in 3D, but it is untenable in 2D due to the lack of condensation in such systems. We develop a new microscopic theory that exhibits low temperature superfluidity on a 2D lattice despite the lack of condensation and show that it has surprising properties. Fluctuations play a key role in the stability of this superfluid, and it is more robust than superfluidity in the presence of a BEC. Finally, we discuss the application of this mechanism to produce superfluidity in a 3D system.