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Cooling an Optically Trapped Ultracold Fermi Gas by Periodical Driving
Published on: March 30, 2017
Quantum Enhancement of the Index of Refraction in a Bose-Einstein Condensate
P C Bons1, R de Haas1, D de Jong1
1Nanophotonics, Debye Institute, Center for Extreme Matter and Emergent Phenomena, Utrecht University, P.O. Box 80,000, 3508 TA Utrecht, The Netherlands.
Abstract:
We study the index of refraction of an ultracold bosonic gas in the dilute regime. Using phase-contrast imaging with light detuned from resonance by several tens of linewidths, we image a single cloud of ultracold atoms for 100 consecutive shots, which enables the study of the scattering rate as a function of temperature and density using only a single cloud. We observe that the scattering rate is increased below the critical temperature for Bose-Einstein condensation by a factor of 3 compared to the single-atom scattering rate. We show that current atom-light interaction models to second order of the density show a similar increase, where the magnitude of the effect depends on the model that is used to calculate the pair-correlation function. This confirms that the effect of quantum statistics on the index of refraction is dominant in this regime.
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