The Realization Of Quantum State Control Based On Photonic Crystal Cavity Chain

As a core device of optical communication,photonic crystal cavity has become one of the hot spots in recent years.In this paper,the adiabatic conditions are mainly used to realize the quantum state transmission,phase gates,and three-dimensional entangled states preparation scheme in the atomic and photonic crystal cavity system:1.The quantum state transmission between any two nodes in a one-dimensional photonic crystal cavity chain is studied.We extend it to a two-dimensional photonic crystal cavity.Under adiabatic conditions,the dark state of the atom-photonic crystal cavity-chain coupled model can be used to realize the transmission of quantum states between two cavities in a one-dimensional photonic crystal coupled cavity chain.In the quantum state transmission process,if the coupling strength between the atom and the cavity is large enough,the population of the excited state of the cavity can be ignored,and the system has high fidelity.The effects of the length of the cavity chain,the preparation of the initial state,the attenuation of the cavity,and the coupling strength of the atoms and the cavity on the fidelity of the quantum state transmission are discussed.The above scheme helps to realize a quantum network and provides a theoretical basis for multi-qubit manipulation.2.A scheme for implementing a quantum controllable phase gate in a one-dimensional photonic crystal cavity chain is proposed.The scheme can perform quantum phase gate operation in an odd-numbered cavity of any length,and the system has high fidelity.The conditional phase shift of the two-bit atomic phase gate is neither dependent on the dynamic phase of the eigen energy nor the Berry phase in the evolution process.It originates from the evolution of the dark state itself.3.The specific form of the dark state and the preparation of the three-dimensional entangled state of the photonic crystal cavity in the coupling of two five-level atoms and single-mode photonic crystal cavity is studied.Under dark state condition,the atom is always in the ground state,and the excited state of the cavity can be neglected under certain conditions.On this basis,this scheme can not consider the spontaneous emission of atoms and the dissipation of the photonic crystal cavity.