Control of entanglement and non-classical effects in circuit QED

Through manipulating the external capacitor or external classical microwave impulse, the coupling between superconducting qubits and cavity can be manipulated, the entanglement effect between field modes can be enhanced and the decoherence effect can be effectively suppressed. Further investigations indicate that, the time evolution of the quantum entanglement between field modes is always accompanied by the synchronous changes of certain non-classical effect. Once entanglement sudden death occurs, the non-classical effects disappear.