We discuss a possible origin of the experimentally observed nonlinear contribution to the shift ΔTc = Tc − Tc 0 of the critical temperature Tc in an atomic Bose-Einstein condensate (BEC) with respect to the critical temperature Tc 0 of an ideal gas. We found that accounting for a nonlinear (quadratic) Zeeman effect (with applied magnetic field closely matching a Feshbach resonance field B0) in the mean-field approximation results in a rather significant renormalization of the field-free nonlinear contribution b2, namely, Tc/Tc 0 ≃ b2* (a/λT)2 (where a is the s-wave scattering length, λT is the thermal wavelength at Tc 0) with b2* = γ2b2 and γ = γ(B0). In particular, we predict b2* ≃ 42.3 for the B0 ≃ 403 G resonance observed in the 39K BEC.
Sergeenkov, S., Briscese, F., Grether, M., de Llano, M. (2015). Origin of a nonlinear contribution to the shift of the critical temperature in atomic Bose-Einstein condensates. JETP LETTERS, 101(6), 376-379 [10.1134/S0021364015060119].
Origin of a nonlinear contribution to the shift of the critical temperature in atomic Bose-Einstein condensates
Briscese F.;
2015-01-01
Abstract
We discuss a possible origin of the experimentally observed nonlinear contribution to the shift ΔTc = Tc − Tc 0 of the critical temperature Tc in an atomic Bose-Einstein condensate (BEC) with respect to the critical temperature Tc 0 of an ideal gas. We found that accounting for a nonlinear (quadratic) Zeeman effect (with applied magnetic field closely matching a Feshbach resonance field B0) in the mean-field approximation results in a rather significant renormalization of the field-free nonlinear contribution b2, namely, Tc/Tc 0 ≃ b2* (a/λT)2 (where a is the s-wave scattering length, λT is the thermal wavelength at Tc 0) with b2* = γ2b2 and γ = γ(B0). In particular, we predict b2* ≃ 42.3 for the B0 ≃ 403 G resonance observed in the 39K BEC.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
