Splitting Of Ultracold Atoms By Shortcuts To Adiabaticity And Its Applictaions

Quantum information,quantum simulation,quantum sensor and precise measurement are the main researches of current quantum information science and technology.Due to the high coherence and volatility of Bose-Einstein condensates(BECs),BEC has a great application prospects in quantum simulation,quantum sensor and quantum interference.In particular,the study of cold-atom interferometer and its coherent manipulation is of great significance in both fundamental theoretical research and practical applications.A slow adiabatic splitting is generally used to achieve coherent splitting,but the long time required for the adiabatic process will cause technical noise and additional phase diffusion,which will affect the performance of interferometers.So,how to achieve a fast and stable non-adiabatic splitting is one of the research hotspots in this field.Shortcuts to Adiabaticity(STA)can be used to accelerate a quantum adiabatic process,then achieve effective suppression of noise,decoherence,errors and other factors.In this thesis,shortcuts to adiabaticity is used to study a fast non-adiabatic splitting of cold atoms in a double well,its application in atomic interference is also discussed.The results of the thesis are as follows:Firstly,the inverse engineering based on variational approximation is to be designed dynamics equations of system,we achieve a fast and stable splitting of cold atoms in a double well.And considering the influence of nonlinear interactions between atom-atom,the high-fidelity splitting designed by STA is completed in a short evolution time.Secondly,the above work is extended from the Gross-Pitaevskii(GP)mean field theory to many-body theory for discussion.Multiconfigurational time-dependent Hartree method for bosons(MCTDHB)theory is introduced to describe a splitting dynamics of many-body bosons,and the splitting of cold atoms are numerically simulated in the many-body theory.Then we verify the effectiveness of above STA technique in many-body theory.