We apply linear-response analysis of the Gross-Pitaevskii equation to obtain the excitation frequencies of a Bose-Einstein condensate confined in a time-averaged orbiting potential trap. Our calculated values are in excellent agreement with those observed in a recent experiment.
We present a topical review of the development of finite-temperature field theories of Bose-Einstein condensation in weakly interacting atomic gases. We highlight the difficulties in obtaining a consistent finite-temperature theory that has a gapless excitation spectrum in accordance with Goldstone's theorem and which is free from both ultraviolet and infrared divergences. We present results from the two consistent theories developed so far. These are the Hartree-Fock-Bogoliubov theory within the Popov approximation and a many-body T-matrix approach which we have termed gapless-Hartree-Fock-Bogoliubov (GHFB). Comparison with the available experimental results is made and the remaining difficulties are highlighted.
The physical properties and stability of a trapped Bose{Einstein condensate are strongly in uenced by the presence of a net attractive interaction between the particles. In this Letter we describe the spatial distribution, stability, collisional loss rates, and lifetimes for this situation in a weakly interacting trapped atomic gas in the context of mean eld theory. The experimentally important case of 7 Li is discussed in some detail. We show how the condensate contracts and the mean eld becomes unstable as the number of atoms in the condensate are increased. We further show how the number of atoms is limited by the rapid increase in collisional loss rates associated with the contraction of the condensed atomic cloud.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.