Color-map method to eliminate qubit frequency crowding in a quantum computing chip

Patent metadata

Field	Value
Publication number	US-12039402-B2
Application number	US-202016998851-A
Country	US
Kind code	B2
Filing date	Aug 20, 2020
Priority date	Aug 20, 2020
Publication date	Jul 16, 2024
Grant date	Jul 16, 2024

Abstract

A method of frequency allocation in a quantum device having a plurality of qubits includes determining a plurality of frequency groups based on a configuration of the plurality of qubits; determining, for each of the plurality of qubits, a qubit frequency; assigning a frequency group from the plurality of frequency groups to each of the plurality of qubits based on each respective qubit frequency; determining for at least one qubit of the plurality of qubits whether a frequency collision exists between the at least one qubit and neighboring qubits in the plurality of qubits based on the qubit frequency of the at least one qubit and at least one qubit frequency of the neighboring qubits; and adjusting the frequency of the at least one qubit based on the determination whether a frequency collision exists between the at least one qubit and said neighboring qubits in the plurality of qubits. A non-transitory computer-readable medium for frequency allocation in a quantum device includes instructions to perform the method.

First claim

We claim:

1. A method of frequency allocation in a quantum chip having a plurality of qubits, comprising:
determining, by a computer system a plurality of frequency groups based on a configuration of the plurality of qubits, wherein each frequency group of the plurality of frequency groups has a range of frequencies;
determining, by the computer system, for each of the plurality of qubits, a qubit frequency;
assigning a frequency group from the plurality of frequency groups to each of the plurality of qubits based on each respective qubit frequency;
determining, by the computer system, for at least one qubit of the plurality of qubits that a frequency collision does not exist between said at least one qubit and neighboring qubits in the plurality of qubits based on the qubit frequency of said at least one qubit and at least one qubit frequency of the neighboring qubits; and
adjusting on the quantum chip, the frequency of each of the at least one qubit to have a frequency in the range of frequencies of the frequency group to which that qubit was assigned based on the determination that a frequency collision does not exist between said at least one qubit and said neighboring qubits in the plurality of qubits.

2. The method according to claim 1 , wherein the determining for the at least one qubit of the plurality of qubits whether a frequency collision exists between said at least one qubit and said neighboring qubits in the plurality of qubits comprises determining whether a neighboring qubit has a qubit frequency that falls within the frequency group of the at least one qubit.

3. The method according to claim 1 , wherein the determining for the at least one qubit of the plurality of qubits whether a frequency collision exists between said at one qubit and neighboring qubits in the plurality of qubits comprises determining whether a neighboring qubit has a frequency group that is the same as the frequency group of the at least one qubit.

4. The method according to claim 1 , wherein the determining for the at least one qubit of the plurality of qubits whether a frequency collision exists between said at least one qubit and neighboring qubits in the plurality of qubits comprises a neighboring qubit having a frequency group that is incompatible with the frequency group of the at least one qubit based on a defined set of design rules associated with the configuration of the plurality of qubits.

5. The method according to claim 1 , wherein the adjusting the frequency of the at least one qubit comprises assigning a frequency group for each of the qubits.

6. The method according to claim 1 , wherein prior to the adjusting the frequency of the at least one qubit, determining an amount of adjusting needed for the at least one qubit to have a resonant frequency which falls within the frequency range of the assigned frequency group.

7. The method according to claim 1 , wherein the determining the plurality of frequency groups comprises maximizing a margin between a mean frequency of a range of frequencies in at least one of the plurality of frequency groups and a potentially active collision band boundary frequencies of collision bands arising in the configuration of the plurality of qubits.

8. The method according to claim 7 , wherein the maximizing the margin comprises including an additional margin based on manufacturing tolerances of the quantum chip.

9. The method of claim 7 , wherein the maximizing the margin comprises providing margins so as to achieve collision avoidance in the quantum chip.

10. The method according to claim 1 , wherein the assigning the frequency group in the plurality of frequency groups for the plurality of qubits based on each respective qubit frequency comprises assigning a frequency group starting with a qubit having the fewest neighbors or starting with a qubit having the most frequency group choices.

11. The method according to claim 1 , further comprising: increasing, by the computer system, a number of frequency groups of the plurality of frequency groups based on a determination that a defined tuning precision is needed that is higher than an existing tuning precision, and decreasing when the frequency range within each group of frequencies is made larger.

12. The method according to claim 1 , wherein the determining, for each of the plurality of qubits, a qubit frequency comprises: determining for a first qubit a first qubit frequency, determining for a second qubit a second qubit frequency, and determining for a third qubit a third qubit frequency, wherein the third qubit is a control qubit provided between the first and second qubits, wherein a difference between the first and third frequencies is greater than a certain margin frequency and a difference between the second and third frequencies is greater than the certain margin frequency to substantially avoid frequency collisions.

13. The method according to claim 12 , wherein a frequency in a first group of qubit frequencies is set equal to the first qubit frequency, and where a frequency in a second group of qubit frequencies is set equal to the second qubit frequency, and where a frequency in a third group of qubit frequencies is set equal to the third qubit frequency.

14. A non-transitory computer-readable medium for frequency allocation in a quantum chip having a plurality of qubits, the computer-readable medium having instructions that, when executed by a computer system, cause the computer system to:
determine, by the computer system, a plurality of frequency groups based on a configuration of the plurality of qubits, wherein each frequency group of the plurality of frequency groups has a range of frequencies;
determine, by the computer system, for each of the plurality of qubits, a qubit frequency; assign, by the computer system, a frequency group from the plurality of frequency groups to each of the plurality of qubits based on each respective qubit frequency;
determine, by the computer system, for at least one qubit of the plurality of qubits whether a frequency collision exists between said at least one qubit and neighboring qubits in the plurality of qubits based on the qubit frequency of said at least one qubit and at least one qubit frequency of the neighboring qubits; and
adjust, on the quantum chip, the frequency of each of the at least one qubit to have a frequency in the range of frequencies of the frequency group to which that qubit was assigned based on the determination that a frequency collision does not exist between said at least one qubit and neighboring qubits in the plurality of qubit.

15. The non-transitory computer-readable medium according to claim 14 , wherein the computer-readable medium has instructions that, when executed by a computer system, cause the computer system to determine whether a neighboring qubit has a qubit frequency that falls within the frequency group of the at least one qubit.

16. The non-transitory computer-readable medium according to claim 14 , wherein the computer-readable medium has instructions that, when executed by a computer system, cause the computer system to determine whether a neighboring qubit has a frequency group that is the same as the frequency group of the at least one qubit.

17. The non-transitory computer-readable medium according to claim 14 , wherein the computer-readable medium has instructions that, when executed by a computer system, cause the computer system to adjust the frequency of the at least one qubit by assigning a frequency group for each of the qubits.

18. The non-transitory computer-readable medium acco

Assignees

• IBM

Inventors

• Hertzberg Jared Barney
• Rosenbluth Alan E
• Shao Dongbing

Classifications

• G06N10/00 Primary

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