Non-Equilbrium Fermi Gases
Technical Report,01 Mar 2013,29 Feb 2016
North Carolina State University Raleigh United States
Pagination or Media Count:
During this period, we made important breakthroughs in the optical control of two-body interactions in ultra-cold gases. We have studied magnetic Feshbach resonances in an optically-trapped mixture of the two lowest hyperfine states of a 6Li Fermi gas, using two optical fields to create a darkstate in the closed molecular channel. In the experiments, the narrow Feshbach resonance is tuned by up to 3 G. For the broad resonance, thespontaneous lifetime is increased from 0.5 ms for single field tuning to 0.4 s at the dark state resonance, despite the large background scatteringlength.A major breakthrough in our understanding is the experimental verification of a new model of light-induced loss spectra, employing continuum-dressed basis states, which agrees in shape and magnitude with all of our loss measurements for both broad and narrow resonances.Using this model, we show that our method substantially reduces the two-body loss rate compared to single field methods for same tuning range.