Relative phase based manipulation of quantum entanglement and measurement of supercurrent

We investigate the quantum entanglement and supercurrent of coupling superconducting qubits in circuit QED system. We compare the effect of the relative phase of the coupling qubits on the concurrence and supercurrent when the microwave field is initially in coherent state, even coherent state and odd coherent state. The results show that entanglement death can be avoided via manipulating the relative phase only in the coherent state since the improvement for entanglement death is unsatisfactory in the even coherent state and odd coherent state.