  We have performed precision microwave spectroscopy on ultra-cold Rb-87
confined in a magnetic trap, both above and below the Bose-condensation
transition. The cold collision shifts for both normal and condensed clouds were
measured, which allowed the intra- and inter-state density correlations
(characterized by sometimes controversial "factors of two") to be determined.
Additionally, temporal coherence of the normal cloud was studied, and the
importance of mean-field and velocity-changing collisions in preserving
coherence is discussed.
