Flying-Qubit Gate Control with a Tunable Waveguide Coupler

Towards distributed quantum computing, the logical operation of flying qubits leads to the flying-qubit gate control problem. This paper studies the design of single flying-qubit gates using a superconducting qubit with a tunable waveguide coupler. We show that, without microwave driving, only phase gates are realizable, and we derive an analytical expression of the tuning scheme for arbitrary phase gates. The resulting scheme is demonstrated by numerical examples.