Sympathetic Cooling with Two Atomic Species in an Optical Trap

Abstract

We simultaneously trap ultracold lithium and cesium atoms in an optical dipole trap formed by the focus of a CO2 laser and study the exchange of thermal energy between the gases. The optically cooled cesium gas efficiently decreases the temperature of the lithium gas through sympathetic cooling. Equilibrium temperatures down to 25 microK have been reached. The measured cross section for thermalizing 133Cs-7Li collisions is 8 x 10(-12) cm(2), for both species unpolarized in their lowest hyperfine ground state. Besides thermalization, we observe evaporation of lithium purely through elastic cesium-lithium collisions (sympathetic evaporation).

XΣ+1andaΣ+Staanum1, Pashov2, Knöckel3 et al. 2007Phys. Rev. A1199592View full textAdd to dashboardCite

“…Cold collisions were studied for Li+Cs pairs through sympathetic cooling by Mudrich et al [21] and trap loss measurements by Schlöder et al [20]. The latter work gives loss rates for processes where excited states are involved and thus cannot be related directly to cold collision calculations which are now possible with the ground state potentials reported in this paper.…”

“…Therefore, the aim of our experimental work is to collect experimental data on both ground states and to fit accurate experimental potential energy curves simultaneously for both states -the indispensable starting point for a study of the molecular structure of LiCs or for modeling of cold collision processes on the Li(2s)+Cs(6s) asymptote. We apply these potential curves within a cou- pled channels model in order to explain our experimental observations and also to compute collision properties for comparing recent results of sympathetic cooling of Li by Cs [21] The article is organized as follows: The experimental setup and excitation schemes are presented in Section II. In Section III we describe the analysis of the obtained spectra.…”

“…Previ-ously, inelastic collisions [20] and sympathetic cooling of Li by Cs in an optical dipole trap [21] have been studied. Recent theoretical work considers LiCs in strong dc electric fields and its influence on rovibrational dynamics [22] and Li-Cs collision cross sections [9].…”

Static and rotating domain-wall cross patterns in Bose-Einstein condensates

“…We also note in passing that work is currently in progress towards the creation of two-component BECs with different atomic species, such as 41 K: 87 Rb [9] and 7 Li: 133 Cs [10]. In that case, |∆| may take values very different from those given in Eqs.…”

“…To construct a DW cross in a similar fashion, we also start from the TF ansatz (10), and then remove two quarter-planes in each component, multiplying the expression (10) by (1/2) …”