1→N quantum controlled phase gate realized in a circuit QED system

Abstract

We propose an effective method to realize the quantum phase gate of one qubit simultaneously controlling N qubits. We use the system in which the transmon qubits are capacitively coupled to a superconducting transmission line resonator driven by a strong microwave field. In our scheme, the phase gate can be realized in a time (nanosecond-scale) much shorter than decoherence time (microsecond-scale), and it is more immune to the 1/f charge noise and has longer dephasing time due to the favorable properties of the transmon qubits in the system.