M.H.S. Amin, et al.

A superconducting qubit implementation is proposed that takes the advantage of both charge and phase degrees of freedom. Superpositions of flux states in a superconducting loop with three Josephson junctions form the states of the qubit. The charge degree of freedom is used to readout and couple the qubits. Cancellation of first-order coupling to charge and flux fluctuations, at the working point of the qubit, protects it from the dephasing due to these sources.