Coherence, Correlations, and Collisions: What One Learns about Bose-Einstein Condensates from Their Decay

We have used three-body recombination rates as a sensitive probe of the statistical correlations between atoms in Bose-Einstein condensates (BEC) and in ultracold noncondensed dilute atomic gases. We infer that density fluctuations are suppressed in the BEC samples. We measured the three-body recombination rate constants for condensates and cold noncondensates from number loss in the ${F=1,m}_f=-1\mathrm{}$ hyperfine state of ${}^{87}\mathrm{Rb}$. The ratio of these is $7.4\left(2.6\right)$ which agrees with the theoretical factor of $3!$ and demonstrates that condensate atoms are less bunched than noncondensate atoms.