Construction Of Entanglement Gate Based On Optimal Control Of Geometric Evolution

Quantum information and quantum computation is a new-rising discipline which is the product of the combination of quantum theory and modern information science.Realizing the application of quantum computer is the important purpose of studying quantum information and quantum computing theory.Furthermore,the application prospect of quantum computer is extremely attractive because it has far more computing and information processing power than classical computer.However,there are some difficulties still in the implementation of quantum computer,the most important of which is how to maintain the coherence of quantum system in the calculate process and how to achieve error-correct.With the advances in quantum computing,the entanglement can be used in quantum computing to reduce the communication complexity between different parts of the quantum computer,to realize the redundant coding without copy,and to perform the error diagnosis without destroying the coding state,etc.Therefore,the faithful entanglement gates contributes greatly to the realization of a quantum computer.Furthermore,because of the superior security of high-dimensional entanglement to qubit(i.e.,two-dimensional)entanglement,it is necessary to construct high-dimensional entanglement gates.In this thesis,by using the counterdiabatic driving method,we propose a novel scheme for constructing an error-insensitive three-dimensional entanglement gate based on quantum Zeno dynamics and adiabatic geometric quantum computation(AGQC)in an atom-cavity-fiber system.The added counterdiabatic Hamiltonian does not introduce additional unaccessible ground-state coupling,and only the shapes and phases of the initial adiabatic classical-field pulse need to be modified.We pick appropriate parameters and discuss feasibility,effectiveness and robustness against system’s decay of the scheme by numerical simulations.Furthermore,by using the optimal control technology,we establish an optimal strategy which can suppress effectively the effect of the control error of Rabi frequency or detuning on fidelity of entanglement gate.In particular,by selecting appropriate optimized parameter,our scheme can simultaneously suppress or even eliminate the effect of both control errors.