Finite Temperature Correlated Mean Field Treatments and Information Theory

P. Grangé, J. Cugnon, A. Lejeune

H. G. Miller, R. M. Quick, R. Rossignoli +1 more

R. Rossignoli, Angel Ricardo Plastino

An extended mean-field approximation for statistical operators is derived within the context of information theory. The ensuing scheme is applied to (many) boson mean-field approaches within a completely general statistical framework. Numerical examples are given within the context of the finite-temperature anharmonic oscillator problem. Fluctuations are also discussed.

David A. W. Hutchinson, R. J. Dodd, Keith R. Burnett

We present predictions for the frequencies of collective modes of trapped Bose-condensed ${}^{87}\mathrm{Rb}$ atoms at finite temperature. Our treatment includes a self-consistent treatment of the effects upon the mean field from finite- $T$ excitations and the anomalous average. This is the first gapless [A. Griffin, Phys. Rev. B 53, 9341 (1996)] calculation of this type for a trapped Bose-Einstein condensed gas. The corrections quantitatively account for the downward shift in the $m\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}2$ excitation frequencies observed in recent experiments as the critical temperature is approached.

R. Rossignoli, R. M. Quick, H. G. Miller

G. Puddu