Constructing quantum process for quantum processors

Patent metadata

Field	Value
Publication number	US-10325218-B1
Application number	US-201715419682-A
Country	US
Kind code	B1
Filing date	Jan 30, 2017
Priority date	Mar 10, 2016
Publication date	Jun 18, 2019
Grant date	Jun 18, 2019

Abstract

In a general aspect, a quantum process for execution by a quantum processor is generated. In some instances, test data representing a test output of a quantum process are obtained. The test data are obtained based on a value assigned to a variable parameter of the quantum process. An objective function is evaluated based on the test data, and an updated value is assigned to the variable parameter based on the evaluation of the objective function. The quantum process is provided for execution by a quantum processor, and the quantum process provided for execution has the updated value assigned to the variable parameter.

First claim

What is claimed is:

1. A method comprising:
identifying a variable parameter of a quantum process;
obtaining test data representing a test output of the quantum process, wherein the test data are generated by a quantum simulator or quantum computer executing the quantum process with a first value assigned to the variable parameter;
by operation of a data processing apparatus, evaluating an objective function based on the test output of the quantum process;
modifying the quantum process by assigning a second, different value to the variable parameter based on the evaluation of the objective function; and
providing, for execution by a quantum processor, the quantum process having the second value assigned to the variable parameter, wherein modifying the quantum process improves the execution of the quantum process by the quantum processor.

2. The method of claim 1 , wherein the objective function is evaluated using the test data and training data for the quantum process, the training data comprising training outputs associated with respective training inputs.

3. The method of claim 1 , wherein the quantum process comprises a quantum logic circuit configured to generate an ansatz in a quantum variational eigensolver (QVE).

4. The method of claim 3 , wherein the objective function is evaluated based on the test data and training data for the quantum logic circuit, the training data comprising a ground state energy for a molecular structure.

5. The method of claim 1 , wherein the quantum process comprises a quantum logic circuit, and the variable parameter comprises a parameter of the quantum logic circuit.

6. The method of claim 1 , wherein the quantum process comprises a quantum logic gate, and the variable parameter comprises a parameter of a control sequence that causes the quantum processor to execute the quantum logic gate.

7. The method of claim 6 , wherein the quantum processor comprises a superconducting quantum circuit, and the variable parameter comprises a parameter of a control signal that causes the superconducting quantum circuit to execute the quantum logic gate.

8. The method of claim 1 , wherein the test data are obtained by the quantum processor executing the quantum process having the first value assigned to the variable parameter.

9. The method of claim 1 , wherein the test data are obtained by a classical processor simulating the quantum process having the first value assigned to the variable parameter.

10. The method of claim 1 , wherein the variable parameter comprises a first variable parameter in a set of variable parameters of the quantum process, the test data are based on a first set of values being assigned to the set of variable parameters, and the method comprises:
assigning a second, different set of values to the set of variable parameters based on the evaluation of the objective function, the second set of values comprising the second value assigned to the first variable parameter; and
providing, for execution by the quantum processor, the quantum process having the second set of values assigned to the set of variable parameters.

11. The method of claim 10 , comprising executing an iterative process, each iteration of the iterative process comprising:
obtaining test data for the current iteration of the iterative process, the test data for the current iteration based on a current set of values assigned to the set of variable parameters;
evaluating the objective function based on the test data for the current iteration;
computing updated values for the set of variable parameters based on the evaluation of the objective function; and
assigning the updated values to the set of variable parameters for a subsequent iteration of the iterative process.

12. A computer system comprising:
a quantum simulator or quantum computer;
a data processing apparatus; and
a non-transitory computer-readable medium storing instructions that are operable when executed by the data processing apparatus to perform operations comprising:
obtaining test data representing a test output of a quantum process, wherein the test data are generated by the quantum simulator or quantum computer executing the quantum process with a first value assigned to a variable parameter of the quantum process;
evaluating an objective function based on the test data;
modifying the quantum process by assigning a second, different value to the variable parameter based on the evaluation of the objective function; and
providing, for execution by a quantum processor, the quantum process having the second value assigned to the variable parameter, wherein modifying the quantum process improves the execution of the quantum process by the quantum processor.

13. The computer system of claim 12 , wherein the objective function is evaluated based on the test data and training data for the quantum process, and the training data comprises training outputs associated with respective training inputs.

14. The computer system of claim 12 , wherein the quantum process comprises a quantum logic circuit configured to generate an ansatz in a quantum variational eigensolver (QVE), the objective function is evaluated based on the test data and training data for the quantum logic circuit, and the training data comprise a ground state energy for a molecular structure.

15. The computer system of claim 12 , wherein the quantum process comprises a quantum logic circuit, and the variable parameter comprises a parameter of the quantum logic circuit.

16. The computer system of claim 12 , wherein the quantum process comprises a quantum logic gate, and the variable parameter comprises a parameter of a control sequence that causes the quantum processor to execute the quantum logic gate.

17. The computer system of claim 12 , wherein obtaining the test data comprises:
providing, for execution by the quantum processor, the quantum process having the first value assigned to the variable parameter; and
receiving the test data from the quantum processor, wherein the test data are generated by the quantum processor executing the quantum process having the first value assigned to the variable parameter.

18. The computer system of claim 12 , wherein obtaining the test data comprises:
providing, for simulation by a classical processor, the quantum process having the first value assigned to the variable parameter; and
receiving the test data from the classical processor, wherein the test data are generated by the classical processor simulating the quantum process having the first value assigned to the variable parameter.

19. The computer system of claim 12 , wherein the variable parameter comprises a first variable parameter in a set of variable parameters of the quantum process, the test data are based on a first set of values being assigned to the set of variable parameters, and the operations comprise:
assigning a second, different set of values to the set of variable parameters based on the evaluation of the objective function, the second set of values comprising the second value assigned to the first variable parameter; and
providing, for execution by the quantum processor, the quantum process having the second set of values assigned to the set of variable parameters.

20. The computer system of claim 12 , comprising executing an iterative process, each iteration of the iterative process comprising:
obtaining test data for the current iteration of the iterative process, the test data for the current iteration based on a current value assigned to the

Assignees

• Rigetti & Co Inc

Inventors

• Zeng William J
• Rigetti Chad Tyler

Classifications

• G06N20/00

  Machine learning · CPC title

• G01R31/3177

  Testing of logic operation, e.g. by logic analysers · CPC title

• G06N10/00 Primary

  Quantum computing, i.e. information processing based on quantum-mechanical phenomena · CPC title

• G06N10/20

  Models of quantum computing, e.g. quantum circuits or universal quantum computers · CPC title

• G06N10/60

  Quantum algorithms, e.g. based on quantum optimisation, quantum Fourier or Hadamard transforms · CPC title