n-qubit-controlled phase gate with superconducting quantum-interference devices coupled to a resonator -: art. no. 032311

We present a way to realize an n-qubit controlled phase gate with superconducting quantum-interference devices (SQUIDs) by coupling them to a superconducting resonator. In this proposal, the two logical states of a qubit are represented by the two lowest levels of a SQUID. An intermediate level of each SQUID is utilized to facilitate coherent control and manipulation of quantum states of the qubits. It is interesting to note that an n-qubit controlled phase gate can be achieved with n SQUIDs by successively applying a pi/2 Jaynes-Cummings pulse to each of the n-1 control SQUIDs before and after a pi Jaynes-Cummings pulse on the target SQUID.