Lifetime of the Bose Gas with Resonant Interactions

B. S. Rem (1) , A. T. Grier (1) , I. Ferrier-Barbut (1) , U. Eismann (1) , T. Langen (2) , N. Navon (1) , L. Khaykovich (1, 3) , Felix Werner (1) , D. S. Petrov (4, 5) , F. Chevy (1) , C. Salomon (1)

1 LKB (Lhomond) - Laboratoire Kastler Brossel
2 Vienna Center for Quantum Science and Technology
3 Department of Physics [Ramat-Gan]
4 LPTMS - Laboratoire de Physique Théorique et Modèles Statistiques
5 Russian Research Center Kurchatov Institute, Kurchatov Square, 123182 Moscow, Russia

We study the lifetime of a Bose gas at and around unitarity using a Feshbach resonance in lithium~7. At unitarity, we measure the temperature dependence of the three-body decay coefficient $L_{3}$. Our data follow a $L_3\,{=}\,\lambda_{3} / T^{2}$ law with $\lambda_{3}\,{=}\,2.5(3)_{\rm stat}(6)_{sys}\times10^{-20} (\muK)^2cm^6s^{-1}$ and are in good agreement with our analytical result based on the zero-range theory. Varying the scattering length $a$ at fixed temperature, we investigate the crossover between the finite-temperature unitary region and the previously studied regime where $|a|$ is smaller than the thermal wavelength. We find that $L_{3}$ is continuous across resonance, and over the whole $a\,{<}\,0$ range our data quantitatively agree with our calculation.

Domaines: Gaz Quantiques [cond-mat.quant-gas]

B. S. Rem, A. T. Grier, I. Ferrier-Barbut, U. Eismann, T. Langen, et al.. Lifetime of the Bose Gas with Resonant Interactions. 2012. ⟨hal-00768038⟩