Impedance-matched microwave quantum circuit systems

Patent metadata

Field	Value
Publication number	US-10740688-B2
Application number	US-201615377005-A
Country	US
Kind code	B2
Filing date	Dec 13, 2016
Priority date	Mar 11, 2016
Publication date	Aug 11, 2020
Grant date	Aug 11, 2020

Abstract

In a general aspect, a microwave quantum circuit includes an on-chip impedance matching circuit. In some cases, a microwave quantum circuit includes a dielectric substrate, a quantum circuit device on the substrate, and an impedance matching circuit device on the substrate. The quantum circuit device includes a Josephson junction, and the impedance matching circuit device is coupled to the quantum circuit device on the substrate.

First claim

The invention claimed is:

1. A microwave quantum circuit system comprising:
a dielectric substrate;
a quantum circuit device on the dielectric substrate, the quantum circuit device comprising a Josephson junction; and
a linear impedance matching circuit device on the dielectric substrate, the linear impedance matching circuit device coupled to the quantum circuit device and comprising a ladder network of inductors and shunt capacitors;
wherein the quantum circuit device comprises a parametric amplifier configured to:
provide a gain of at least (4) dB to microwave signals over a bandwidth greater than five hundred (500) MHz, and
provide gain to microwave signals having a nominal frequency between four (4) and ten (10) GHz.

2. The system of claim 1 , wherein the quantum circuit device comprises a qubit device.

3. The system of claim 1 , wherein the parametric amplifier is a Josephson parametric amplifier.

4. The system of claim 1 , wherein the quantum circuit device comprises a superconducting quantum interference device (SQUID), the SQUID comprising multiple Josephson junctions.

5. The system of claim 1 , wherein the linear impedance matching circuit device comprises a series of circuit unit cells, each circuit unit cell comprising an inductor and a shunt capacitor.

6. The system of claim 1 , wherein the linear impedance matching circuit device is configured to communicate microwave signals to the quantum circuit device, the microwave signals having a bandwidth greater than five hundred (500) MHz.

7. The system of claim 1 , comprising a ground conductor, wherein the quantum circuit device and the linear impedance matching circuit device reside in an interior clearance area defined by the ground conductor.

8. The system of claim 1 , comprising a ground conductor, wherein the quantum circuit device, the linear impedance matching circuit device, and the ground conductor are each on a first side of the dielectric substrate in a coplanar waveguide topology.

9. The system of claim 1 , comprising a ground conductor on a first side of the dielectric substrate, wherein the quantum circuit device and the linear impedance matching circuit device are each on a second side of the dielectric substrate opposite the first side in a microstrip topology.

10. The system of claim 1 , comprising a ground conductor defining an interior clearance area, the inductors of the linear impedance matching circuit device comprising meandered conductive traces within the interior clearance area, the shunt capacitors of the linear impedance matching circuit device comprising conductive traces forming interdigitated gaps between the meandered conductive traces.

11. The system of claim 1 , comprising a ground conductor having an interior boundary defining an interior clearance area, wherein the linear impedance matching circuit device comprises elongate conductive traces extending in a first direction from the interior boundary of the ground conductor, the elongate conductive traces spaced apart from each other in a second direction perpendicular to the first direction, and comprising meandered conductive traces between the elongate conductive traces.

12. The system of claim 1 , comprising a ground conductor defining an interior clearance area, wherein the linear impedance matching circuit device comprises meandered conductive traces and elongate conductive traces within the interior clearance area, the longest spatial dimension of the meandered conductive traces being parallel to the longest spatial dimension of the elongate conductive traces.

13. The system of claim 1 , comprising:
an array of quantum circuit devices on the dielectric substrate, each quantum circuit device comprising a Josephson junction; and
an array of linear impedance matching circuit devices on the dielectric substrate, each linear impedance matching circuit device coupled to a respective one of the quantum circuit devices, each of the linear impedance matching circuit devices comprising a ladder network of inductors and shunt capacitors.

14. A method for processing quantum information, comprising:
receiving a microwave signal at a linear impedance matching circuit device on a dielectric substrate, the linear impedance matching circuit device comprising a ladder network of inductors and shunt capacitors; and
communicating the microwave signal to a quantum circuit device coupled to the linear impedance matching circuit device on the substrate, the quantum circuit device comprising a Josephson junction;
wherein communicating the microwave signal to the quantum circuit device comprises communicating the microwave signal to a parametric amplifier on the dielectric substrate, the parametric amplifier configured to:
provide a gain of at least four (4) dB to microwave signals over a bandwidth greater than five hundred (500) MHz, and
provide gain to microwave signals having a nominal frequency between four (4) and ten (10) GHz.

15. The method of claim 14 , wherein the microwave signal has a nominal frequency between four (4) and ten (10) GHz.

16. The method of claim 15 , wherein the microwave signal communicated to the quantum circuit device has a bandwidth greater than five hundred (500) MHz.

17. The method of claim 14 , wherein communicating the microwave signal to the quantum circuit device comprises communicating the microwave signal to a qubit device.

18. The method of claim 14 , wherein communicating the microwave signal to the quantum circuit device comprises communicating the microwave signal to a superconducting quantum interference device (SQUID), the SQUID comprising multiple Josephson junctions.

19. A quantum computing system comprising a quantum circuit system, the quantum circuit system comprising:
a qubit device on a substrate;
a parametric amplifier on the substrate, the parametric amplifier comprising a Josephson junction;
a linear impedance matching circuit device on the substrate, the linear impedance matching circuit device coupled to the qubit device and the parametric amplifier and comprising a ladder network of inductors and shunt capacitors; and
a control system configured to send microwave signals to the qubit device;
wherein the parametric amplifier is configured to provide a gain of at least four (4) dB to microwave signals over a bandwidth greater than five hundred (500) MHz; and
wherein the parametric amplifier is configured to provide gain to microwave signals having a nominal frequency between four (4) and ten (10) GHz.

20. The quantum computing system of claim 19 , wherein the parametric amplifier is a Josephson parametric amplifier.

21. The quantum computing system of claim 19 , wherein the control system comprises a digitizer that receives an output from the parametric amplifier and generates a digital signal based on the output.

22. The quantum computing system of claim 21 , wherein the control system comprises a computer system that receives the digital signal from the digitizer.

23. The quantum computing system of claim 19 , wherein the control system comprises a pump tone source that provides a pump tone signal to the parametric amplifier.

24. The quantum computing system of claim 19 , the quantum circuit system comprising:
an array of qubit devices on the substrate;
an array of parametric amplifiers on the substrate, each parametric amplifier comprising a Josephson junction; and
an array of linear impedance matching circuit devices on the substrat

Assignees

• Rigetti & Co Inc
• Rigetti & Co Inc

Inventors

• Selvanayagam Michael Karunendra
• Rigetti Chad T
• Sete Eyob A
• Reagor Matthew J

Classifications

• G06N10/20

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

• H10N60/815

  for Josephson-effect devices · CPC title

• H10N60/12

  Josephson-effect devices · CPC title

• H10N69/00

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