The Generation Of The Entanglement State Via Optimal Adiabatic Passage In Cavity QED System

Quantum information science is based on the principle of the superposition of states of quantum mechanics. As a booming frontier subject, quantum information science receives high attention from the international academics. The carrier of quantum information is the quantum state, and an effective method to manipulate the quantum state is the adiabatic passage technology, the physical principle of which is to drive the quantum system evolution by slowly changing the external time-dependent driving source. The advantages of the adiabatic method are that the results are insensitive to the fluctuation of the parameters and there is no need to control the evolution time strictly. As a vital medium to store and transform the energy, cavity quantum electrodynamics system (c-QED system) is a mature and effective system. The premise and vitality to realize and manipulate the quantum state is to search the optimal parameters which satisfy the adiabatic condition. Otherwise, the adiabatic passage technology usually requires a long evolution time which will increase the influences caused by decoherence and the dissipation of the system. In this way the adiabatic scheme degradeds and even fails. So, shortcut to the adiabaticity is an urgent issue in the current of adiabatic method for restraining the decoherence and dissipation.Our paper is to optimize the traditional adiabatic passage in the c-QED system.The main efforts are to find the optimal pulses for the operation and preparation of quantum states, and to shortcut the adiabatic passage within the multi particle systems. The details are as follows:In Chapter 1, the background of the study, the proposition and definition of adiabatic passage and shortcut to adiabaticity are introduced, and the major research subjects and the organization of the dissertation are given at the end of this chapter.In Chapter 2, the scheme to drive three atoms into a singlet state in an optical cavity via adiabatic passage of a dark state is proposed. Then, we analytically solve a range of optimal pulse parameters via adiabatic condition and verify the validity of this range through the numerical simulation. The results of the numerical simulation also show that our scheme possesses the advantages of the adiabatic passage, which is insensitive to the imprecision of evolution time and the decoherence.In Chapter 3, the scheme to shortcut the adiabatic passage for the fast population transfer based on the invariant-based inverse engineering in cavity QED system is proposed. The scheme emploies the cavity field as a medium for the energy transfer between the photons and realizes the application of the accelerated method in multi-atom. The numerical results show that our scheme can combine the robustness and efficiency within the process of population transfer.In Chapter 4, the scheme to shortcut the adiabatic passage for population transfer and maximum entanglement generation between two atoms based on the transitionless quantum driving in c-QED system is proposed. We analytically solve the countadiabatic Hamiltonian for two atoms which are trapped in a cavity, and design the extern driving pulses and the reliable physical configuration through the large-detuning interaction. Finally, we analyze the acceleration effect and the influence of the decohenence in the system.Finally, the results are summarized at the end of the paper.