Quantum entanglement and control in a capacitively coupled charge qubit circuit

The macroscopic quantum entanglement in capacitively coupled SQUID (superconducting quantum interference device)-based charge qubits is investigated theoretically. The entanglement characteristic is discussed by employing the quantum Rabi oscillations and the concurrence. An interesting conclusion is obtained, i.e., the magnetic fluxes \varPhi_x1 and \varPhi_x2 through the superconducting loops can adjust the entanglement degree between the qubits.