Bose-Einstein Condensation, Phase Coherence, and Two-Fluid Behavior in 4He

It is shown that the assumption that the many particle wave functions describing superfluid ⁴He have some phase coherence properties of correlated basis functions provides a new explanation of the link between Bose-Einstein condensation and two fluid behavior. This assumption also implies that the condensate fraction is proportional to the superfluid fraction, in agreement with experiment, and provides a simple quantitative explanation of the anomalous reduction in spatial order and liquid density, observed as the temperature is lowered in superfluid ⁴He.