High phase space density loading of a falling magnetic trap
Abstract
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 . 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.
Cite
@article{arxiv.1802.08983,
title = {High phase space density loading of a falling magnetic trap},
author = {Ido Almog and Jonathan Coslovsky and Gil Loewenthal and Arnaud Courvoisier and Nir Davidson},
journal= {arXiv preprint arXiv:1802.08983},
year = {2018}
}