Experimental Study Of Two Dimensional Spin-orbit Coupling On Ultracold Bose Gas

This thesis is about the research of superfluid,topological insulator and other prob-lems,which are all based on Spin-Orbit Coupling(SOC)on Bose-Einstein Condensate(BEC).In the research,we studied different properties of the SOC system,and devel-oped several techniques.Spin-Orbit Coupling in solid system bring about much rich physics and applica-tions,such as topological insulators,Majorana Fermions,spin devices,etc.Ultracold atoms is one of the simplest multi-body system.The platform is highly pure and con-trollable,thus ideal for the study of SOC.In this thesis,I first introduced the setups and techniques to realize and study BEC and SOC.New setups and techniques include Cicero time series control system,Kapitza-Dirac diffraction calibration,Bragg spectroscopy and magnetics stabilization system.We employed Bragg spectroscopy to get the whole excitation spectrum of 1D SOC system and further studied the "phonon-maxon-roton" structure.We found that near the phase transition point,roton and phonon both tends to decrease.Then based on the Raman coupling techniques,we proposed a minimal scheme and realized a 2D SOC system.The scheme requires no phase locking or fine tuning of the optical poten-tials.On the other hand,the system can transfer from 1D to 2D with small heating and topological stability.Based on the realization,the topological phase transition and spin-texture of the system is then studied.After that,we proposed another scheme which is a upgraded version of this original one,to guarantee the complete C4 symmetry.The setup is simpler,more compact and more stable.Because of this,the life time of the system is also highly improved.We further studied the topological phase diagram and band structures of the system.Artificial Spin-Orbit Coupling on Ultracold atom has a much rich physics in it.It can contribute great to the studies of superfluid,topological insulators and etc.The two-dimensional SOC we realized can transfer from 1D to 2D with small heating and topological stability.In cold atoms,it offers an important approach to study exotic quantum phase.