Creation And Study Of Ultracold²³Na⁴⁰K Ground-State Molecules

Research about ultracold dipolar molecules has emerged in recent years.Com-pared to ultracold atoms,ultracold heteronuclear molecules possess rich internal struc-ture and permanent electric dipole moment which allows long-range dipole-dipole inter-action.Because of these advantages,ultracold dipolar molecules show great potential in quantum simulation,precision measurements,quantum information,quantum com-putation and ultracold chemistry.This thesis describes the construction of the experimental apparatus of ultracold polar molecules,the creation of singlet rovibrational ground state 23Na40K molecules and the experiment about magnetic tuned atom-molecule Feshbach resonances.Three main parts are contained in this thesis.Firstly,the creation of the 23Na,40K Bose-Fermi quantum degenerate gas and the formation of ulracold fermionic Feshbach molecules of 23Na40K are presented.Secondly,using stimulated Raman adiabatic passage(STIRAP),Feshbach molecules are transfered to the singlet rovibrational ground state.About 1.6×104 ground state molecules are created,with a trap lifetime?200ms.Thirdly,Feshbach resonances in ultracold collisions between ground-state molecules and atoms are observed for the first time.We find 11 resonant loss features in collisions between 23Na40K ground-state molecules and 40K atoms.