  In this paper, we propose a scheme to realize three-qubit quantum phase gate
of one qubit simultaneously controlling two target qubits using four-level
superconducting quantum interference devices (SQUIDs) coupled to a
superconducting resonator. The two lowest levels |0> and |1> of each SQUID are
used to represent logical states while the higher energy levels |2> and |3> are
utilized for gate realization. Our scheme does not require adiabatic passage,
second order detuning, and the adjustment of the level spacing during gate
operation which reduce the gate time significantly. The scheme is generalized
for an arbitrary n-qubit quantum phase gate. We also apply the scheme to
implement three-qubit quantum Fourier transform. key words: quantum phase gate,
superconducting quantum interference devices (SQUIDs), superconducting
resonator, quantum Fourier transform
