Superconducting qubit and resonator system based on the Josephson ring modulator

Patent metadata

Field	Value
Publication number	US-12016254-B2
Application number	US-202218055655-A
Country	US
Kind code	B2
Filing date	Nov 15, 2022
Priority date	Nov 27, 2019
Publication date	Jun 18, 2024
Grant date	Jun 18, 2024

Abstract

A superconducting quantum mechanical device includes first, second, third and fourth Josephson junctions connected in a bridge circuit having first, second and third resonance eigenmodes. The device also includes first and second capacitor pads. The first and second capacitor pads and the bridge circuit form a superconducting qubit having a resonance frequency corresponding to the first resonance eigenmode. The device further includes first and second resonator sections. The first and second resonator sections and the bridge circuit form a resonator having a resonance frequency corresponding to the second resonance eigenmode. The device also includes a source of magnetic flux arranged proximate the bridge circuit. The source of magnetic flux is configured to provide, during operation, a magnetic flux through the bridge circuit to cause coupling between the first, second and third resonance eigenmodes when the third resonance eigenmode is excited.

First claim

I claim:

1. A superconducting quantum-mechanical device comprising:
a bridge circuit;
a superconducting qubit comprising:
the bridge circuit,
a first pad electrically coupled to the bridge circuit, and
a second pad electrically coupled to the bridge circuit;

a resonator comprising:
the bridge circuit,
a first resonator section electrically coupled to the bridge circuit, and
a second resonator section electrically coupled to the bridge circuit; and

a ground pad that surrounds three sides of the first pad, and
wherein the second pad is configured to be electromagnetically coupled to a qubit feedline of the superconducting quantum-mechanical device, and wherein a space between the second pad and the qubit feedline defines a capacitor configured to provide capacitance across the bridge circuit located between the first pad and the second pad.

2. The superconducting quantum-mechanical device of claim 1 , further comprising a source of magnetic flux configured to provide magnetic flux through the bridge circuit, wherein the magnetic flux activates coupling between the superconducting qubit and the resonator.

3. The superconducting quantum-mechanical device of claim 2 , wherein the bridge circuit comprises a first eigenmode, a second eigenmode and a third eigenmode.

4. The superconducting quantum-mechanical device of claim 3 wherein the superconducting qubit comprises a first resonance frequency corresponding to the first eigenmode and wherein the resonator comprises a second resonance frequency corresponding to the second eigenmode.

5. The superconducting quantum-mechanical device of claim 4 wherein the first eigenmode and the second eigenmode are coupled by excitation of the third eigenmode.

6. The superconducting quantum-mechanical device of claim 5 wherein the magnetic flux excites the third eigenmode.

7. The superconducting quantum-mechanical device of claim 4 wherein the first resonance frequency and the second resonance frequency are orthogonal.

8. The superconducting quantum-mechanical device of claim 1 wherein the bridge circuit comprises a plurality of Josephson junctions, and wherein the plurality of Josephson junctions comprises a first Josephson junction, a second Josephson junction, a third Josephson junction and a fourth Josephson junction.

9. The superconducting quantum-mechanical device of claim 8 wherein a first node is located between the first Josephson junction and the fourth Josephson junction, a second node is located between the second Josephson junction the third Josephson junction, a third node is located between the first Josephson junction and the third Josephson junction, and a fourth node is located between the third Josephson junction and the fourth Josephson junction.

10. The superconducting quantum-mechanical device of claim 9 , wherein the first pad is electrically coupled to the first node and the second pad is electrically coupled to the second node.

11. The superconducting quantum-mechanical device of claim 9 , wherein the first resonator section is electrically coupled to the third node and the second resonator section is electrically coupled to the fourth node.

12. The superconducting quantum-mechanical device of claim 2 , wherein the source of magnetic flux comprises a magnetic material.

13. The superconducting quantum-mechanical device of claim 2 , wherein the source of magnetic flux comprises an electrical current carrying element.

14. The superconducting quantum-mechanical device of claim 1 , wherein the superconducting qubit and the resonator are formed on the same substrate.

15. The superconducting quantum-mechanical device of claim 1 , wherein the first resonator section and the second resonator section comprise a material of at least one of Al, Nb, NbTiN, NbN or TiN.

16. The superconducting quantum-mechanical device of claim 8 , wherein the plurality of Josephson junctions comprise a material of at least one of Al, Nb, NbTiN, NbN or TiN.

17. The superconducting quantum-mechanical device of claim 3 , further comprising a resonator feedline configured to be electromagnetically coupled to the resonator.

18. The superconducting quantum-mechanical device of claim 17 , wherein a space between the resonator feedline and the first resonator section defines another capacitor.

19. The superconducting quantum-mechanical device of claim 17 , wherein the resonator feedline is configured to excite the second eigenmode.

20. The superconducting quantum-mechanical device of claim 3 , wherein the qubit feedline is configured to excite the first eigenmode.

Assignees

• IBM

Inventors

• Abdo Baleegh

Classifications

• G06N10/40

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

• H10N60/805

  for Josephson-effect devices · CPC title

• H03F19/00

  Amplifiers using superconductivity effects · CPC title

• H03D7/005

  by means of superconductive devices · CPC title

• H10N60/126 Primary

  comprising metal borides, e.g. MgB2 · CPC title