Adaptive quantum circuit construction for multiple-controlled-NOT gates

Patent metadata

Field	Value
Publication number	US-11609751-B2
Application number	US-201816224912-A
Country	US
Kind code	B2
Filing date	Dec 19, 2018
Priority date	Dec 19, 2018
Publication date	Mar 21, 2023
Grant date	Mar 21, 2023

Abstract

In an embodiment, a method includes measuring a first number of control qubits in a quantum algorithm, wherein a quantum circuit representation of the quantum algorithm includes a multiple-controlled-NOT gate. In an embodiment, a method includes measuring a second number of ancilla qubits in a quantum computer. In an embodiment, a method includes comparing the first number and the second number to determine an optimum compilation method for a quantum circuit. In an embodiment, a method includes compiling, in response to the comparison determining the second number is greater than one and less than the difference of the first number and 2, a quantum circuit from the quantum algorithm using a hybrid method.

First claim

What is claimed is:

1. A method comprising:
measuring a first number of control qubits in a quantum algorithm, wherein a quantum circuit representation of the quantum algorithm includes a multiple-controlled-NOT gate;
measuring a second number of ancilla qubits in a quantum computer;
comparing the first number and the second number to determine an optimum compilation method for a quantum circuit; and
compiling, in response to the comparison determining the second number is greater than one and less than the difference of the first number and 2, a quantum circuit from the quantum algorithm using a hybrid method.

2. The method of claim 1 , wherein the hybrid method includes a basic method and an advanced method.

3. The method of claim 2 , further comprising:
determining a difference between the first number of control qubits and the second number of ancilla qubits.

4. The method of claim 3 , further comprising:
controlling, in response to the difference being less than five, a first subset of the number of control qubits with the basic method and a second subset of the number of control qubits with the advanced method.

5. The method of claim 3 , further comprising:
controlling, in response to the difference being less than or equal to four, a first subset of the number of control qubits with the advanced method.

6. The method of claim 5 , further comprising:
writing a result of the first subset of the number of control qubits to an ancilla qubit.

7. The method of claim 6 , further comprising:
controlling a second subset of the number of control qubits and the ancilla qubit with the basic method.

8. A computer usable program product comprising a computer-readable storage medium, and program instructions stored on the storage medium, the stored program instructions comprising:
program instructions to measure a first number of control qubits in a quantum algorithm, wherein a quantum circuit representation of the quantum algorithm includes a multiple-controlled-NOT gate;
program instructions to measure a second number of ancilla qubits in a quantum computer;
program instructions to compare the first number and the second number to determine an optimum compilation method for a quantum circuit; and
program instructions to compile, in response to the comparison determining the second number is greater than one and less than the difference of the first number and 2, a quantum circuit from the quantum algorithm using a hybrid method.

9. The computer usable program product of claim 8 , wherein the program instructions are stored in a computer readable storage medium in a data processing system, and wherein the computer usable code is transferred over a network from a remote data processing system.

10. The computer usable program product of claim 8 , wherein the program instructions are stored in a computer readable storage medium in a server data processing system, and wherein the computer usable code is downloaded over a network to a remote data processing system for use in a computer readable storage medium associated with the remote data processing system.

11. The computer usable program product of claim 8 , wherein the hybrid method includes a basic method and an advanced method.

12. The computer usable program product of claim 11 , the stored program instructions further comprising:
program instructions to determine a difference between the first number of control qubits and the second number of ancilla qubits.

13. The computer usable program product of claim 12 , the stored program instructions further comprising:
program instructions to control, in response to the difference being less than five, a first subset of the number of control qubits with the basic method and a second subset of the number of control qubits with the advanced method.

14. The computer usable program product of claim 12 , the stored program instructions further comprising:
program instructions to control, in response to the difference being less than or equal to four, a first subset of the number of control qubits with the advanced method.

15. The computer usable program product of claim 14 , the stored program instructions further comprising:
program instructions to write a result of the first subset of the number of control qubits to an ancilla qubit.

16. The computer usable program product of claim 15 , the stored program instructions further comprising:
program instructions to control a second subset of the number of control qubits and the ancilla qubit with the basic method.

17. A computer system comprising a quantum processor, a computer-readable memory, and a computer-readable storage medium, and program instructions stored on the storage medium for execution by the quantum processor via the memory, the stored program instructions comprising:
program instructions to measure a first number of control qubits in a quantum algorithm, wherein a quantum circuit representation of the quantum algorithm includes a multiple-controlled-NOT gate;
program instructions to measure a second number of ancilla qubits in a quantum computer;
program instructions to compare the first number and the second number to determine an optimum compilation method for a quantum circuit; and
program instructions to compile, in response to the comparison determining the second number is greater than one and less than the difference of the first number and 2, a quantum circuit from the quantum algorithm using a hybrid method.

18. The computer system of claim 17 , wherein the hybrid method includes a basic method and an advanced method.

19. The computer system of claim 18 , the stored program instructions further comprising:
program instructions to determine a difference between the first number of control qubits and the second number of ancilla qubits.

20. The computer system of claim 19 , the stored program instructions further comprising:
program instructions to control, in response to the difference being less than five, a first subset of the number of control qubits with the basic method and a second subset of the number of control qubits with the advanced method.

Assignees

• IBM

Inventors

• Hu Shaohan
• Harry Putra Rudy Raymond
• Wood Stephen
• Pistoia Marco
• Gambetta Jay M

Classifications

• G06N10/20

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

• G06N10/70

  Quantum error correction, detection or prevention, e.g. surface codes or magic state distillation · CPC title

• G06N10/80

  Quantum programming, e.g. interfaces, languages or software-development kits for creating or handling programs capable of running on quantum computers; Platforms for simulating or accessing quantum computers, e.g. cloud-based quantum computing · CPC title

• G06N10/40 Primary

  Physical realisations or architectures of quantum processors or components for manipulating qubits, e.g. qubit coupling or qubit control · CPC title

• G06F8/41 Primary

  Compilation · CPC title