Tuning quantum discord in Josephson charge qubits system

A type of two qubits Josephson charge system is constructed, and properties of the quantum discord (QD) as well as the differences between thermal QD and thermal entanglement are investigated. A detailed calculation shows that the magnetic flux is more efficient than the voltage in tuning QD. By choosing proper system parameter the maximum QD can be realized in our two qubits Josephson charge system.