An ultracold Bose-Fermi gas mixture of 40K and 87Rb atoms has tunable interspecies interactions\ and therefore provides a fantastic platform for exploring not only few-body physics such\ as Feshbach molecule formation and Efimov trimers, but also many-body physics including Bose\ polarons, quantum Hall physics and so on. In this thesis, I present experimental evidence of Bose\ polarons in cold atoms obtained using radio-frequency spectroscopy to measure the excitation spectrum\ of fermionic 40K impurities resonantly interacting with a BEC of 87Rb atoms. These Bose\ polarons originate from the dressing of an impurity coupled to its environment, which is an important\ paradigm in quantum many-body physics. I also present initial work that launches an\ exciting new direction for our experiment, which is exploring rotating quantum gases. Goals for\ this work include studying both rotating Bose and Fermi superfluids with tunable interactions as\ well as working toward rapidly rotating quantum gases in the quantum Hall regime. For these\ goals, a new all-optical trap for rotating gases was designed, implemented, and tested using a 87Rb\ Bose-Einstein condensate.
CY - Boulder, CO DA - 08-2016 N2 -An ultracold Bose-Fermi gas mixture of 40K and 87Rb atoms has tunable interspecies interactions\ and therefore provides a fantastic platform for exploring not only few-body physics such\ as Feshbach molecule formation and Efimov trimers, but also many-body physics including Bose\ polarons, quantum Hall physics and so on. In this thesis, I present experimental evidence of Bose\ polarons in cold atoms obtained using radio-frequency spectroscopy to measure the excitation spectrum\ of fermionic 40K impurities resonantly interacting with a BEC of 87Rb atoms. These Bose\ polarons originate from the dressing of an impurity coupled to its environment, which is an important\ paradigm in quantum many-body physics. I also present initial work that launches an\ exciting new direction for our experiment, which is exploring rotating quantum gases. Goals for\ this work include studying both rotating Bose and Fermi superfluids with tunable interactions as\ well as working toward rapidly rotating quantum gases in the quantum Hall regime. For these\ goals, a new all-optical trap for rotating gases was designed, implemented, and tested using a 87Rb\ Bose-Einstein condensate.
PB - University of Colorado Boulder PP - Boulder, CO PY - 2016 EP - 120 TI - Bose polarons and rotating gases in an ultracold Bose-Fermi gas mixture of 40K and 87Rb atoms VL - Ph.D. ER -