Title :
Sympathetic evaporative cooling of /sup 6/Li by /sup 7/Li
Author :
Truscott, A.G. ; Strecker, K.E. ; Hulet, R.G.
Author_Institution :
Rice Quantum Inst., Rice Univ., Houston, TX, USA
Abstract :
Summary form only given. The last five years has seen an explosive growth in activity in the field of quantum degenerate gases, and there are now many realizations of Bose-Einstein condensation (BEC) of trapped atomic gasses. However, only one experiment has produced a quantum degenerate Fermi gas. The ultimate goal of the experiment discussed here is to achieve a BCS phase transition in a trapped gas of fermionic /sup 6/Li atoms. This requires a phase-space density that is much higher than that needed for BEC, as the temperature must be made much less than the Fermi temperature.BEC in trapped gases has only been achieved using forced evaporative cooling. Since this method depends on elastic collisions, however, it fails for an ultracold Fermi gas, as the Pauli principle forbids s-wave collisions between identical fermions. To circumvent this obstacle, we simultaneously trap a /sup 7/Li-/sup 6/Li mixture, and use rf-induced evaporation to cool /sup 7/Li. /sup 6/Li is then cooled via thermalizing elastic collisions with the /sup 7/Li. The clover-leaf-type magnetic trap is loaded from a two-species magneto-optical trap (MOT).
Keywords :
BCS theory; Bose-Einstein condensation; lithium; magneto-optical effects; phase transformations; radiation pressure; /sup 6/Li; /sup 7/Li; 7Li-6Li mixture; BCS phase transition; Bose-Einstein condensation; Fermi temperature; Pauli principle; elastic collisions; fermionic /sup 6/Li atoms; forced evaporative cooling; phase-space density; quantum degenerate Fermi gas; quantum degenerate gases; rf-induced evaporation; simultaneously trap; sympathetic evaporative cooling; trapped gas; two-species magneto-optical trap; Atom optics; Charge carrier processes; Cooling; Gases; Magnetic devices; Magnetic resonance; Magnetoelasticity; Optical pumping; Optical scattering; Temperature;
Conference_Titel :
Quantum Electronics and Laser Science Conference, 2001. QELS '01. Technical Digest. Summaries of Papers Presented at the
Conference_Location :
Baltimore, MD, USA
Print_ISBN :
1-55752-663-X
DOI :
10.1109/QELS.2001.962226