Before revision: By differentiating the current equation and using substitution, one obtains the inductance term : From these equations, one can observe that the Josephson Inductance term is non-linear; because of this, the energy level spacings are no longer degenerate, restricting the dynamics of the system to the two qubit states.
After revision: By differentiating the current equation and using substitution, one obtains the inductance term : From these equations, Josephson the Josephson Inductance term is non-linear; because of this, the energy level spacings are no longer degenerate, restricting the dynamics of the system to the two qubit states.