Research On The Ultrafast Preparation Of Coherent Superposition States Based On Kinetic Invariant Accelerated Adiabatic Shortcut Technology

Quantum adiabatic approximation theory plays an important role in quantum mechanics and it has been widely used in various quantum fields.For instance,Adiabatic Approximation Theory has solved many difficult problems that puzzle us in quantum theory and information science and technology.However,because of the adiabatic process is affected by quantum decoherence,environmental noise and system error,and there are a series of slow-changing physical processes in the adiabatic process itself,the control results of quantum states will be greatly affected by these unnecessary factors.For this reason,people are looking for ways to accelerate the quantum adiabatic process,which can achieve the same effect of adiabatic process,in order to achieve stable preparation of high fidelity quantum states.In this paper,quantum invariants and their inverse control methods are used to study the ultra-fast non-adiabatic manipulation of coherent superposition states in a four-IeveNtype system,and to optimize the design of environmental noise and system error.This paper mainly sets forth the following points:First,the development of coherent superposition state preparation by adiabatic shortcut technology is introduced,as well as its current status and some applications in practice.Generally speaking,adiabatic shortcut technology is used to the problem of slow adiabatic process.Decoherence in excessive adiabatic process will seriously affect the accuracy of experimental results.The adiabatic shortcut is a measurement of eliminating the non-adiabatic effect in the process of adiabatic evolution by using auxiliary Hamiltonian.There,the simple applications of friction-free dynamics,quantum invariant dynamics and optimization theory in two-level and three-level systems are introduced,and their advantages and disadvantages are compared and analyzed.Second,the Dynamical invariant theory is used to study the fabrication of quantum coherent superposition states in two-level atomic systems by accelerating quantum adiabatic shortcuts.By designing time-dependent dynamic invariants and using inverse control method,the time-dependent Hamiltonian is designed to realize the complete population transfer.Combining with time-dependent perturbation theory,the phase noise and system error are optimized.The method is extended to three-level atomic system.The population is completely transferred by the method of dynamic invariants,which achieves the control of quantum states.Third,the Dynamical invariant theory is extended to accelerate the adiabatic shortcut for the preparation of quantum coherent superposition states in four-level atomic systems.The results show that the Dynamica1 invariant theory accelerates adiabatic evolution by choosing appropriate affix states as evolution paths,and the means of optimization theory eliminates the system errors,and we obtain the target states quickly.Finally,we achieve the aim of the fast preparation of coherent superposition states.