Coupled-line bus to suppress classical crosstalk for superconducting qubits

Patent metadata

Field	Value
Publication number	US-11538854-B2
Application number	US-202016833479-A
Country	US
Kind code	B2
Filing date	Mar 27, 2020
Priority date	Mar 27, 2020
Publication date	Dec 27, 2022
Grant date	Dec 27, 2022

Abstract

A system includes a first quantum circuit plane that includes a first qubit, a second qubit and a third qubit. A coupled-line bus is coupled between the first qubit and the second qubit. A second circuit plane is connected to the first quantum circuit plane, comprising a control line coupled to the third qubit. The control line and the coupled-line bus are on different planes and crossing over each other, and configured to mitigate cross-talk caused by the crossing during signal transmission.

First claim

What is claimed is:

1. A system, comprising:
a first quantum circuit plane comprising:
a first qubit;
a second qubit;
a third qubit; and
a coupled-line bus coupled between the first qubit and the second qubit; and

a second circuit plane connected to the first quantum circuit plane, comprising a control line coupled to the third qubit, wherein the control line and the coupled-line bus are on different planes and cross over each other and are configured to mitigate cross-talk caused by the crossing over of the control line and the coupled-line during signal transmission.

2. The system of claim 1 , wherein the coupled-line bus is configured to transmit differential mode signals between the first and second qubits of the first quantum circuit plane.

3. The system of claim 1 , wherein the first quantum circuit plane and the second circuit plane are located on separate chips of a flip chip and connected together via bump bonds.

4. The system of claim 1 , wherein the control line is a feed line that is configured to transmit a signal to drive the third qubit.

5. The system of claim 1 , wherein the control line is a readout resonator that is configured to read a signal from the third qubit.

6. The system of claim 1 , wherein the control line is orthogonal to the coupled-line bus at the crossing over of the control line and the coupled-line bus to suppress an inductive coupling between the control line and the coupled-line bus.

7. The system of claim 1 , wherein the coupled-line bus is a dual strip coplanar waveguide (CPW) transmission-line resonator.

8. The system of claim 1 , wherein the first qubit and the second qubit are coupled to the coupled-line bus differentially and configured to excite only an odd mode of the coupled-line bus.

9. The system of claim 8 , wherein a cross talk from the control line to the coupled-line bus is configured to generate a common mode signal on the coupled-line bus that is electrically mitigated.

10. The system of claim 1 , wherein a suppression ratio of a crosstalk between the coupled-line bus and the control line depends on a gap between lines of the coupled-line bus.

11. A method of reducing crosstalk between different planes of qubits, the method comprising:
providing a coupled-line bus between a first qubit and a second qubit of a first quantum circuit plane;
providing a control line to a third qubit of the first quantum circuit plane, wherein the control line is on a second circuit plane that is on a different plane than the first quantum circuit plane; and
coupling the first quantum circuit plane to the second circuit plane such that the control line and the coupled-line bus are on different planes and cross over each other, wherein the control line and the coupled-line bus mitigate cross talk caused by the crossing over of the control line and the coupled-line bus during signal transmission.

12. The method of claim 11 , further comprising transmitting differential mode signals between the first and second qubits of the first quantum circuit plane.

13. The method of claim 11 , wherein the first quantum circuit plane and the second circuit plane are located on separate chips and connected together via bump bonds.

14. The method of claim 11 , further comprising driving the third qubit through the control line.

15. The method of claim 11 , further comprising suppressing an inductive coupling between the control line and the coupled-line bus by arranging the control line to be orthogonal to the coupled-line bus.

16. The method of claim 11 , further comprising coupling the first qubit and the second qubit to the coupled-line bus differentially to excite only an odd mode of the coupled-line bus.

17. A quantum circuit structure, comprising:
a coupled-line bus between a first qubit and a second qubit of a first quantum chip; and
a control line to a third qubit, wherein:
the control line that is on a second chip is on a different plane than the first quantum chip,
the second chip is bonded to the first quantum chip via bump bonds, and
the control line and the coupled-line bus are on different planes and cross over each other and configured to mitigate cross talk caused by the crossing over of the control line and the coupled-line bus during signal transmission.

18. The quantum circuit structure of claim 17 , wherein the coupled-line bus is configured to transmit differential mode signals between the first and second qubits of the first quantum chip.

19. The quantum circuit structure of claim 17 , wherein the control line is orthogonal to the coupled-line bus at the crossing to suppress an inductive coupling between the control line and the coupled-line bus.

20. The quantum circuit structure of claim 17 , wherein the first qubit and the second qubit are coupled to the coupled-line bus differentially and configured to excite only an odd mode of the coupled-line bus.

21. The quantum circuit structure of claim 17 , wherein a suppression ratio of a crosstalk between the coupled-line bus and the control line depends on a gap between lines of the coupled-line bus.

22. The quantum circuit structure of claim 17 , wherein the first qubit and the second qubit comprise additional coupling buses in addition to the coupled-line bus.

Assignees

• IBM

Inventors

• Solgun Firat
• Shao Dongbing
• Brink Markus

Classifications

• G06N10/20

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

• H01P3/026 Primary

  Coplanar striplines [CPS] · CPC title

• G06N10/40

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

• H01L27/18 Primary

  Electricity · mapped topic

• H10N69/00 Primary

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