Ground State And Soliton Properties In Spin-orbit Coupled Bose-Einstein Condensates

Spin-orbit coupling(SOC)plays an important role in condensed matter physics,but due to the difficulties to adjust SOC in solid materials,there are many limitations for its deep-study.As a cross field of condensed matter physics,atomic physics,and quantum optics,the ultracold atom quantum platform is of great significance in physical research.Recently,the artificial synthesis of spin-orbit coupling has opened a new door to the ultracold atomic quantum system and a large number of theories and experiments have been verified in the SOC system.As a platform that can simulate condensed matter physics,the ultracold atom system has also become one of the current hot spots.With the deepening of research,the Spin-Tensor-MomentumCoupling(STMC)system is also realized in the environment of ultracold atoms.As an important branch of nonlinear optics,soliton can correspond to a stable matter wave in a ultracold atomic system.The addition of SOC and STMC breaks the balance between the atomic kinetic energy term and the interaction term in the system,so SOC and STMC play a key role in the formation and properties of solitons.In this paper,the imaginary-time evolution and the variational-method are used to study the bright solitons in SOC-BECs system and STMC-BECs system.The research content mainly includes using imaginary-time evolution to obtain the ground state of the two systems numerically,and the parameters of variational wave function are adjusted according to the principle of energy minimization.Finally,the dynamic properties of the soliton are obtained through real-time evolution.The results show that: in both systems,stationary bright solitons can be found through imaginary-time evolution.The variational ansatz in this article agrees well with the ground state wave function;SOC and STMC play an important role in the formation of bright solitons.To the key role,after the SOC is turned off,the SOC soliton will split into two waves to propagate,and the STMC soliton will keep the shape unchanged to propagate after the STMC is turned off.We attribute this difference to the symmetry of SOC and STMC system.In addition,we use variational-method to study the effect of adding three-body interaction to the spin-1/2 system.The results of the study show that: after adding the three-body interaction,the phase transition conditions and the position of triple point have been changed.