Quantum coupler facilitating suppression of ZZ interactions between qubits

Patent metadata

Field	Value
Publication number	US-11600658-B2
Application number	US-202016917016-A
Country	US
Kind code	B2
Filing date	Jun 30, 2020
Priority date	Jun 30, 2020
Publication date	Mar 7, 2023
Grant date	Mar 7, 2023

Abstract

Devices and/or computer-implemented methods to facilitate ZZ cancellation between qubits are provided. According to an embodiment, a device can comprise a coupler device that operates in a first oscillating mode and a second oscillating mode. The device can further comprise a first superconducting qubit coupled to the coupler device based on a first oscillating mode structure corresponding to the first oscillating mode and based on a second oscillating mode structure corresponding to the second oscillating mode. The device can further comprise a second superconducting qubit coupled to the coupler device based on the first oscillating mode structure and the second oscillating mode structure.

First claim

What is claimed is:

1. A computer-implemented method, comprising:
generating, by a system operatively coupled to a processor, an exchange coupling of a first superconducting qubit and a second superconducting qubit with a first oscillating mode structure and a second oscillating mode structure of a coupler device; and
producing, by the system, an entangling quantum gate between the first superconducting qubit and the second superconducting qubit.

2. The computer-implemented method of claim 1 , wherein at least one of the first superconducting qubit or the second superconducting qubit comprises at least one of a transmon qubit, a fixed frequency qubit, or a fixed frequency transmon qubit.

3. The computer-implemented method of claim 1 , wherein the coupler device comprises at least one of a two junction qubit, a fixed frequency coupler, a multimode two junction coupler, a flux tunable coupler, a tunable coupler qubit, a flux tunable coupler qubit, a tunable qubit, a tunable bus, or a flux tunable qubit bus.

4. The computer-implemented method of claim 1 , wherein the first oscillating mode structure and the second oscillating mode structure respectively correspond to a first oscillating mode and a second oscillating mode of the coupler device, and wherein the first oscillating mode and the second oscillating mode are indicative of symmetric and antisymmetric combinations of excitations associated with a first Josephson Junction and a second Josephson Junction of the coupler device.

5. The computer-implemented method of claim 1 , further comprising:
generating, by the system, an equal exchange coupling of the first superconducting qubit and the second superconducting qubit with the first oscillating mode structure and the second oscillating mode structure to suppress ZZ interactions between the first superconducting qubit and the second superconducting qubit over a defined range of qubit frequencies, thereby facilitating at least one of: reduced quantum gate errors associated with at least one of the first superconducting qubit or the second superconducting qubit; increased speed of a quantum gate comprising the first superconducting qubit and the second superconducting qubit; or at least one of improved fidelity, improved accuracy, or improved performance of a quantum processor comprising the coupler device, the first superconducting qubit, and the second superconducting qubit.

6. A computer-implemented method, comprising:
coupling, by a system operatively coupled to a processor, a first superconducting qubit to a first oscillating mode structure corresponding to a first oscillating mode of a coupler device;
coupling, by the system, a second superconducting qubit to a second oscillating mode structure corresponding to a second oscillating mode of the coupler device; and
detuning, by the system, the coupler device from the first oscillating mode or the second oscillating mode.

7. The computer-implemented method of claim 6 , wherein at least one of the first superconducting qubit or the second superconducting qubit comprises at least one of a transmon qubit, a fixed frequency qubit, or a fixed frequency transmon qubit.

8. The computer-implemented method of claim 6 , wherein the coupler device comprises at least one of a two junction qubit, a fixed frequency coupler, a multimode two junction coupler, a flux tunable coupler, a tunable coupler qubit, a flux tunable coupler qubit, a tunable qubit, a tunable bus, or a flux tunable qubit bus.

9. The computer-implemented method of claim 6 , wherein the first oscillating mode and the second oscillating mode are indicative of symmetric and antisymmetric combinations of excitations associated with a first Josephson Junction and a second Josephson Junction of the coupler device.

10. The computer-implemented method of claim 6 , further comprising:
coupling, by the system, the first superconducting qubit to the first oscillating mode structure and the second superconducting qubit to the second oscillating mode structure to reduce a direct exchange coupling between the first superconducting qubit and the second superconducting qubit and to suppress ZZ interactions between the first superconducting qubit and the second superconducting qubit, thereby facilitating at least one of: reduced quantum gate errors associated with at least one of the first superconducting qubit or the second superconducting qubit; increased speed of a quantum gate comprising the first superconducting qubit and the second superconducting qubit; or at least one of improved fidelity, improved accuracy, or improved performance of a quantum processor comprising the coupler device, the first superconducting qubit, and the second superconducting qubit.

Assignees

• IBM

Inventors

• Finck Aaron
• Blair John
• Carniol April
• Dial Oliver
• Kumph Muir

Classifications

• G06N10/00

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

• H10N60/12

  Josephson-effect devices · CPC title

• H10N60/805

  for Josephson-effect devices · CPC title

• H10N69/00 Primary

  Integrated devices, or assemblies of multiple devices, comprising at least one superconducting element covered by group H10N60/00 · CPC title

• G06N10/70

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