Studies Of Dark-Bright Vector Solitons In Spin-Orbit Coupled Bose-Einstein Condensate

The spin-orbit coupled Bose-Einstein Condensates(BECs)of cold atomic physics is an important experimental operating platform for exploring the unknown domain of quantum mechanics,novel atomic physics behaviors are constantly being discovered for people to open up a deep research field.The basic properties of spin-orbit coupled BECs can be ex-plored and discovered by systematically studying a series of properties of various solitons.First of all,this paper construct a quasi one-dimensional theory model of spin orbit cou-pled BECs,and use the variational method and the imaginary time evolution method to solve the coupled nonlinear schrodinger equation,a numerical method for the spin orbit coupled bose gas mixture of spin orbit coupling strength and Raman laser and the detuning between the atomic energy level of a variety of phase state of equilibrium phase diagram.It is found that there are three kinds of solitons states in condensates,which are dark solitons,dark-bright vector solitons and fringe solitons.At the same time,the results of Crank-Nicolson algorithm based on real-time evolution and imaginary time evolution were compared and verified under the simplified background,and are found to be consistent in real time.Secondly,in this paper,the effects of spin-orbit coupling intensity,detuning between Raman laser and atomic energy level,and interatomic interaction intensity on the density distribution,amplitude and width of dark-bright vector solitons in BECS are studied and verified by comparison with each other.the effects of spin-orbit coupling intensity,detuning between Raman laser and atomic energy level,and atomic interaction intensity on the density distribution of dark-bright vector solitons in BECs are studied.In order to further understand the effects of the three factors on the dark-bright solitons in BECS,the properties of the dark-bright solitons are studied from the aspects of amplitude and width,and the comparison between them is verified.The results show that the density distribution of dark-bright solitons is the balance result of the interaction among the spin-orbit coupling effect,the nonlinear repulsion interaction and the detuning of atoms.Finally,the dynamic properties of dark bright vector solitons under different spin-orbit coupling strengths are studied.By analyzing the dynamic evolution of the vector dark-bright solitons under typical physical parameters in the spin-orbit coupled BECS,it is found that the shape and phase of the dark-bright solitons remain unchanged in the parameter region,which indicates that the phenomenon of mixed dynamics does not occur,and the dark-bright vector solitons are highly stable.Then the dynamics evolution of two stationary dark-bright solitons in spin-orbit coupled BECS under different parameters is studied.The results show that increasing the strength of the spin-orbit coupling is equal to increasing the strength of the repulsive interaction between atoms,which leads to the transition from the attractive interaction to the repulsive interaction.