Narrow Feshbach Resonance In Ultracold Fermi Atoms Of ~6Li

With the development of laser cooling and trapping methods,the ultracold Fermi gases have become a hot topic in atomic,molecular,and optical physics.Feshbach resonance is an essential tool to control the interaction between atoms in ultracold quantum gases,which can be widely used to realize the molecular Bose-Einstein condensation and BCS superfluid.In this dissertation,a quickly tunable large field magnet system has been constructed with a magnetic field up to 1200 Gauss and stability better than 10 mGauss.The magnetic field could be transferred within microseconds.Employing cooling methods,such as a Zeeman slower,magneto-optical trap,dipole trap,evaporative cooling,we realized the 6Li quantum degeneracy and molecular Bose-Einstein condensation with this precision magnet system.The narrow Feshbach resonance between the two lowest hyperfine states is observed in this dissertation,the measured result shows great agreement with the theoretical calculation and could be used to investigate strongly interacting Fermi gas at narrow Feshbach resonance.We also demonstrate the interaction strength is strongly energy dependent and frequency shift of the RF transition due to the strong interaction at nearrow Feshbach resonance.This dissertation has great significance in controlling magnetic field and researching strongly interacting at narrow Feshbach resonance.