Gravity and Light in Trapped Bose-Condensate

Abstract

The Bose-condensate fraction ρ in a trap of height h and frequency ω in the gravitational field g is macroscopically stable as the condition 4g ħω of a trap potential. The critical temperature Tc, estimated with the use of the variational equation ρ(ω, γ, h, g, Tc)=0, increases $$Tc|_{g \ne 0} >T_c |_{g = 0} $$ in a gravitational field (g≠0) as compared to the case of its absence (g=0), γ is the boson interaction constant. Deformation of a trap by a gravitational field results in a decrease of a number of atomic levels that provides an increase of the critical temperature. The scale of the shift shows, that we deal with a mesoscopic effect, connected with a broken translation symmetry of the system. Laser light ψ contributes to the interaction constant γ between atoms (association of atoms) and to the trap frequency w (nonresonant scattering on atoms). Both these factors are expected to increase this shift.