High phase space density loading of a falling magnetic trap

Ido Almog, Jonathan Coslovsky, Gil Loewenthal, Arnaud Courvoisier*, Nir Davidson

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Loading an ultra-cold ensemble into a static magnetic trap involves unavoidable loss of phase space density when the gravitational energy dominates the kinetic energy of the ensemble. In such a case the gravitational energy is transformed into heat, making a subsequent evaporation process slower and less efficient. We apply a high phase space loading scheme on a sub-doppler cooled ensemble of Rubidium atoms, with a gravitational energy much higher than its temperature of 1μK. Using the regular configuration of a quadrupole magnetic trap, but driving unequal currents through the coils to allow the trap center to fall, we dissipate most of the gravitational energy and obtain a 20-fold improvement in the phase space density as compared to optimal loading into a static magnetic trap. Applying this scheme, we start an efficient and fast evaporation process as a result of the sub-second thermalization rate of the magnetically trapped ensemble.

Original languageEnglish
Article number158
JournalApplied Physics B: Lasers and Optics
Issue number8
StatePublished - 1 Aug 2018
Externally publishedYes


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