Systems, methods, and apparatus for calibrating, controlling, and operating a quantum processor

A method of quantum annealing using a quantum processor comprising a set of qubits, the method comprising:

• establishing a problem Hamiltonian by applying at least one control signal to each qubit;
• establishing an evolution Hamiltonian by applying at least one disordering signal to each qubit;
• annealing towards a target Hamiltonian by gradually removing the disordering signals from each qubit;
• and
• maintaining a substantially fixed dimensionless target Hamiltonian by adjusting the at least one control signal applied to each qubit during the annealing.

A qubit control system comprising:

• a first qubit;
• a second qubit;
• a first multiplier, wherein the first multiplier communicably couples to the first qubit;
• a second multiplier, wherein the second multiplier communicably couples to the second qubit;
• and
• a global signal line, wherein the global signal line communicably couples to both the first multiplier and the second multiplier such that the first multiplier mediates a coupling between the global signal line and the first qubit and the second multiplier mediates a coupling between the global signal line and the second qubit.

A method of applying a dynamic signal to at least two devices in a quantum processor, the method comprising:

• programming a first multiplier to apply a first scaling factor to the dynamic signal in order to accommodate the behavior of a first device in the quantum processor;
• programming a second multiplier to apply a second scaling factor to the dynamic signal in order to accommodate the behavior of a second device in the quantum processor;
• transmitting the dynamic signal through a global signal line;
• communicably coupling the global signal line to the first device in the quantum processor via the first multiplier such that the first multiplier couples a first signal to the first device in the quantum processor, wherein the first signal is the dynamic signal scaled by the first scaling factor;
• and
• simultaneously communicably coupling the global signal line to the second device in the quantum processor via the second multiplier such that the second multiplier couples a second signal to the second device in the quantum processor, wherein the second signal is the dynamic signal scaled by the second scaling factor.

A quantum processor comprising:

• a plurality of qubits;
• a plurality of couplers arranged to selectively communicably couple respective pairs of the qubits in an inter-coupled network such that each qubit communicably couples to at least one other qubit in the inter-coupled network;
• and
• at least two global signal lines including interfaces selectively operable to couple signals to respective ones of pairs of the qubits wherein any two qubits that are communicably coupled together by a respective coupler arc each configured to communicably couple to a different one of the global signal lines.

A method of calibrating a qubit in a quantum processor comprising a plurality of qubits arranged in an inter-coupled network, the method comprising:

• communicatively isolating a pair of coupled qubits from the other qubits in the quantum processor by deactivating any couplings between the pair of qubits and the other qubits in the quantum processor, wherein the pair of qubits comprises a first qubit and a second qubit;
• applying a first signal to the first qubit in the pair of coupled qubits;
• and
• measuring with the second qubit in the pair of coupled qubits a behavior of the first qubit in response to the first signal.

A superconducting quantum processor comprising:

• a plurality of qubits;
• a plurality of couplers that provide communicable coupling between at least some respective pairs of qubits;
• a first set of programming interfaces operable to apply a flux bias to each qubit;
• a second set of programming interfaces operable to apply a dynamic annealing signal to each qubit;
• and
• a third set of programming interfaces operable to apply a dynamic compensation signal to each qubit, wherein each programming interface in the third set of programming interfaces includes a respective multiplier, and wherein each respective multiplier mediates a communicable coupling between a global signal line and a respective qubit.

A superconducting quantum processor comprising:

• a plurality of qubits;
• a plurality of couplers that provide communicable coupling between at least some respective pairs of qubits;
• and
• a set of programming interfaces to:
• establish a problem Hamiltonian by applying at least one control signal to each qubit;
• establish an evolution Hamiltonian by applying at least one disordering signal to each qubit;
• anneal towards a target Hamiltonian by gradually removing the disordering signals from each qubit;
• and
• maintain a substantially fixed dimensionless target Hamiltonian by adjusting the at least one control signal applied to each qubit during the annealing.

A quantum processor comprising:

• a first qubit;
• a first programming interface to apply a first signal to the first qubit;
• and
• a second qubit to measure a behavior of the first qubit in response to the first signal.