Quantum Simulation And Control Of Information Transport In Cavity QED System

The interaction between light and matter is an important element of quantum optics. Quantum information has rapidly developed in recent years. The realization of quantum information processing taking advantage of the tool of quantum optics is a very hot topic. Cavity QED (cavity quantum electrodynamics) is the study of the interaction between cavity field and material in the cavity. People has done a large mount of excellent work studying cavity QED system in quantum information processing, these work plays an important role on establishing the status of the cavity QED system as Quantum Devices. This paper studies the coupled cavities composed of cavity QED system, as well as the cavity QED system coupled with waveguide, for the purpose of serving for the quantum information processing. This paper is divided into seven chapters, with our work included in the chapters from chapter3to chapter7. The structure of this paper is organized as follows:In chapter1, We introduce relationship between quantum information and quantum optics and the development of cavity QED, then give the significance of the study of the spin chain model in the coupled cavities. We also give a brief introduction of the Cavity QED system coupled with the waveguide. Finally, we give the structure of this paper.The second chapter gives the theoretical knowledge which will be needed in this paper. We introduced the quantization of electromagnetic field, the theory of the interaction between the matter and field. Then we briefly introduce adiabatic elimination method theory, dressed states theory, information entropy and entanglement measurement and the theory of photon coherent.In chapter3, a coupled array of N identical cavities, each of which contains a five-level atom, is investigated. The results show that the atoms, via the exchange of virtual photons, can be effectively equal to a spin-1Heisenberg model under certain conditions. By tuning the laser fields, the parameters of the effective Hamiltonian can be controlled.In chapter4, we simulated anisotropic XYZ-spin chain with an array of coupled cavities, each of which contains one four-level atom. The anisotropic parameters of the effective Hamilton can be tuned by controlling the external lasers. The validity of our approximations are confirmed via a numerical simulation. The decoherence can be neglected under current experimental condition. Finally, the conclusions and discussion are given. In chapter5. We introduce the polaritom theory, which is a effective method for the realization of cavity QED system when the cavity QED system works in strong coupled regime. We investigate frequency conversion and entanglement via polariton technique. We analyze the effect of detuning on the efficiency of frequency conversion (EFC). The results show that by adjusting the second mode frequency, the EFC still can be achieved perfectly when the incoming photon is off-resonant. The effect of the spontaneous emission of the atoms on EFC is included.In chapter6, we study the system consisting of a one-dimension waveguide side-coupled with a nonlinear cavity with a lambda-type atom and investigate the controlling of photons transport in one-dimension waveguide through manipulating the atom contained in the cavity. Employing the polariton technique, we show that in the single-photon case, the system can behave as a waveguide coupled to a two-level system. By solving the Schrodinger equation, we show that single photon switch by tuning the Rabi frequency of the classical field. In the two-photon case, the system can behaves like a waveguide coupled to a cascade three-level system. Two-photon quantum correlation in the position variation can be controlled by adjusting the Rabi frequency.In chapter7, we investigate the two-photon transport properties inside one-dimensional waveguide side-coupled to a cavity. The cavity is doped with a four level atom. By employing dressed state basis, we show that the atom-cavity molecule produces a nonlinear interaction. The bunching and antibunching of the transmitted and reflected photons can be observed due to the nonlinearity. By tuning the Rabi frequency of the classical field. the transmission and reflection of the correlated photons can be controlled.