INHIBITION OF COHERENCE IN TRAPPED BOSE-EINSTEIN CONDENSATES

We analyze the dependence of the collapse and revival of many-atom coh erence of a trapped Bose-Einstein condensate on the trap potential, di mensionality of the gas, and atom number fluctuations. We show that in a class of experimentally relevant systems the collapse time vanishes in the limit of a large number of atoms, implying that the trapped Bo se gas cannot sustain a well-defined quantum phase.