Europhys. Lett.
Volume 71, Number 6, September 2005
Page(s) 918 - 924
Section Atomic and molecular physics
Published online 24 August 2005
Europhys. Lett., 71 (6), pp. 918-924 (2005)
DOI: 10.1209/epl/i2005-10181-4

Depolarisation cooling of an atomic cloud

S. Hensler, A. Greiner, J. Stuhler and T. Pfau

5. Physikalisches Institut, Universität Stuttgart Pfaffenwaldring 57, 70550 Stuttgart, Germany

received 9 May 2005; accepted in final form 19 July 2005
published online 24 August 2005

We propose a cooling scheme based on depolarisation of a polarised cloud of trapped atoms. Similar to adiabatic demagnetisation, we suggest to use the coupling between the internal spin reservoir of the cloud and the external kinetic reservoir via dipolar relaxation to reduce the temperature of the cloud. By optical pumping one can cool the spin reservoir and force the cooling process. In case of a trapped gas of dipolar chromium atoms, we show that this cooling technique can be performed continuously and used to approach the critical phase space density for BEC.

39.25.+k - Atom manipulation (scanning probe microscopy, laser cooling, etc.).
34.50.-s - Scattering of atoms and molecules.
32.80.Pj - Optical cooling of atoms; trapping.

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