Parametrically activated quantum logic gates

A computer system comprising:

• one or more processors;
• and
• memory storing instructions that are operable when executed by the one or more processors to perform operations comprising:
• obtaining qubit device design parameters for a plurality of qubit devices, the plurality of qubit devices comprising a fixed-frequency qubit device and a tunable qubit device;
• obtaining a quantum processor circuit design criterion associated with a two-qubit quantum logic gate;
• determining, based on the qubit device design parameters and by operation of one or more processors, an operating parameter for at least one of the plurality of qubit devices under an operating condition, the operating condition comprising a flux modulation applied to the tunable qubit device, wherein the flux modulation varies the amplitude of a magnetic flux applied to the tunable qubit device over time;
• determining that the operating parameter meets the quantum processor circuit design criterion associated with the two-qubit quantum logic gate;
• and
• providing the qubit device design parameters for a quantum processor circuit specification.

A method comprising:

• obtaining qubit device parameters for a plurality of qubit devices in a quantum processor circuit, the plurality of qubit devices comprising a fixed-frequency qubit device and a tunable qubit device;
• and
• based on the qubit device parameters, selecting gate parameters of a two-qubit quantum logic gate for application to a pair of qubits defined by the fixed-frequency qubit device and the tunable qubit device,
• wherein selecting the gate parameters comprises selecting parameters of a control signal for delivery to a control line coupled to the tunable qubit device, and the gate parameters correspond to:
• a modulation amplitude of a flux modulation produced by the control signal;
• and
• a modulation frequency of the flux modulation produced by the control signal, wherein the flux modulation varies the amplitude of a magnetic flux applied to the tunable qubit device over time.