Session KP01 - Poster Session III.
POSTER session, Tuesday afternoon, March 23
Exhibit Hall, GWCC
We present a theoretical model of the formation of quasi-condensate droplets and apply it to recent measurements in an atomic hydrogen BEC. The formation of droplets of quasi-condensate is based on a first-order phase transition treatment. We consider a gas of weakly interacting trapped bosonic atoms in thermal equilibrium, and evaluate the probability of forming a droplet containing a given number of atoms from density fluctuations near the critical conditions. By determining the number of atoms in a droplet and its density as a function of the local gas density, we predict a global density profile that exhibits large distortion from the thermal density profile. We explore the effect of interaction between atoms using the scattering length. In order to compare the results from our model with experimental data obtained in the atomic hydrogen BEC experiment at MIT, we estimate the two-photon absorption lineshape under current experimental conditions, and predict the appearence of an asymmetric component due to the quasi-condensate droplets. The predicted behavior of the asymmetric component is in accordance with observations. We also speculate on the time evolution of the system: the droplets will coalesce to form larger droplets until the final condensate is formed in the center of the trap.