Operating a multi-dimensional array of qubit devices

Patent metadata

Field	Value
Publication number	US-9892365-B2
Application number	US-201515035547-A
Country	US
Kind code	B2
Filing date	Feb 27, 2015
Priority date	Feb 28, 2014
Publication date	Feb 13, 2018
Grant date	Feb 13, 2018

Abstract

In some aspects, a quantum computing system includes a multi-dimensional array of qubit devices. Coupler devices reside at intervals between neighboring pairs of the qubit devices in the multi-dimensional array. Each coupler device is configured to produce an electromagnetic interaction between one of the neighboring pairs of qubit devices. In some cases, each qubit device has a respective qubit operating frequency that is independent of an offset electromagnetic field experienced by the qubit device, and the coupling strength of the electromagnetic interaction provided by each coupler device varies with an offset electromagnetic field experienced by the coupler device. In some cases, readout devices are each operably coupled to a single, respective qubit device to produce qubit readout signals that indicate the quantum state of the qubit device.

First claim

The invention claimed is:

1. A quantum computing system comprising:
a multi-dimensional array of qubit devices, each qubit device having a respective qubit operating frequency that is independent of an offset electromagnetic field experienced by the qubit device; and
coupler devices residing at intervals between neighboring pairs of the qubit devices in the multi-dimensional array, each coupler device being configured to receive coupler control signals that produce an electromagnetic interaction between the respective neighboring pair of qubit devices, each coupler device configured to vary a coupling strength of the electromagnetic interaction according to an offset electromagnetic field experienced by the coupler device,
wherein each of the coupler devices has a respective coupler operating frequency that varies with the offset electromagnetic field experienced by the coupler device, and the coupling strength varies according to the coupler operating frequency,
wherein each of the neighboring pairs of qubit devices comprises a first qubit device having a first qubit operating frequency and a second qubit device having a second, distinct qubit operating frequency,
wherein the coupler control signals each comprise a DC component and an AC component, and the AC component drives the coupler devices at a drive frequency that corresponds to a sum or difference of the first qubit operating frequency and the second qubit operating frequency.

2. The quantum computing system of claim 1 , comprising readout devices associated with the multi-dimensional array of qubit devices, each readout device operably coupled to a single, respective qubit device and configured to produce a qubit readout signal that indicates a state of the respective qubit device, the qubit readout signal produced in response to a readout control signal delivered to the readout device.

3. The quantum computing system of claim 1 , wherein each qubit device has two or more nearest-neighbor qubit devices in the multi-dimensional array, and the qubit operating frequency of each qubit device is distinct from the respective qubit operating frequencies of each nearest-neighbor qubit device.

4. The quantum computing system of claim 1 , wherein the multi-dimensional array defines a first set of intervals along a first dimension of the array and a second set of intervals along a second dimension of the array, a first subset of the coupler devices reside at the first set of intervals, and a second subset of the coupler devices reside at the second set of intervals.

5. The quantum computing system of claim 1 , wherein the multi-dimensional array comprises a two-dimensional array, and the qubit devices define rows and columns of the two-dimensional array.

6. The quantum computing system of claim 1 , wherein the multi-dimensional array comprises a three-dimensional array, and the qubit devices define rows, columns and layers of the three-dimensional array.

7. The quantum computing system of claim 1 , comprising an electromagnetic waveguide system, the electromagnetic waveguide system comprising an interior surface that defines an interior volume of intersecting waveguides, wherein the qubit devices are housed in the electromagnetic waveguide system.

8. The quantum computing system of claim 1 , wherein the coupler device between each neighboring pair of qubit devices comprises:
bias circuitry configured to produce an offset electromagnetic field that tunes the coupler operating frequency of the coupler device; and
coupler circuitry configured to produce the electromagnetic interaction between the neighboring pair of qubit devices.

9. The quantum computing system of claim 8 , wherein, in the coupler device between each neighboring pair of qubit devices:
the bias circuitry is configured to tune the coupler operating frequency to a frequency range associated with at least one of the first qubit operating frequency or the second qubit operating frequency; and
while the coupler operating frequency is tuned to the frequency range, the coupler circuitry is configured to produce the electromagnetic interaction between the neighboring pair of qubit devices by resonating at the drive frequency.

10. The quantum computing system claim 1 , wherein each of the qubit devices is a member of at least two of the neighboring pairs of the qubit devices in the multi-dimensional array.

11. The quantum computing system of claim 1 , wherein each of the qubit devices comprises a charge qubit.

12. The quantum computing system of claim 11 , wherein each of the qubit devices comprises a transmon qubit.

13. The quantum computing system of claim 1 , wherein each of the coupler devices comprises a flux qubit.

14. The quantum computing system of claim 13 , wherein each of the coupler devices comprises a fluxonium qubit.

15. The quantum computing system of claim 14 , wherein each fluxonium qubit comprises a topologically closed capacitance.

16. The quantum computing system of claim 1 , wherein the multi-dimensional array of qubit devices defines distances between neighboring pairs of the qubit devices, and the distances are between 0.2 and 2.0 centimeters.

17. The quantum computing system of claim 1 , wherein the DC component causes the coupler device to experience an offset electromagnetic field, and the offset electromagnetic field experienced by each coupler device tunes the coupler device to a frequency range associated with at least one of the first qubit operating frequency or the second qubit operating frequency.

18. A quantum computing method comprising:
receiving qubit control signals in a multi-dimensional array of qubit devices, each qubit device having a respective qubit operating frequency that is independent of an offset electromagnetic field experienced by the qubit device, the qubit control signal received by each qubit device being configured to manipulate a quantum state of the qubit device; and
receiving coupler control signals at coupler devices, the coupler devices residing at intervals between neighboring pairs of the qubit devices in the multi-dimensional array, the coupler control signal received by each coupler device being configured to produce an electromagnetic interaction between the neighboring pair of qubit devices that the coupler device resides between, a coupling strength of the electromagnetic interaction produced by each coupler device being influenced by an offset electromagnetic field experienced by the coupler device,
wherein each of the coupler devices has a respective coupler operating frequency that varies with the offset electromagnetic field experienced by the coupler device, and the coupling strength varies according to the coupler operating frequency,
wherein each of the neighboring pairs of qubit devices comprises a first qubit device having a first qubit operating frequency and a second qubit device having a second, distinct qubit operating frequency,
wherein the coupler control signals each comprise a DC component and an AC component, and the AC component drives the coupler device at a drive frequency that corresponds to a sum or difference of the first qubit operating frequency and the second qubit operating frequency.

19. The quantum computing method of claim 18 , wherein each qubit control signal comprises a microwave pulse.

20. The quantum computing method of claim 18 , wherein each qubit control signal is configured to execute a single-qubit gate on the qubit device that receives the qubit control signal.

21. The quantum compu

Assignees

• Rigetti & Co Inc

Inventors

• Rigetti Chad Tyler
• Thompson Dane Christoffer

Classifications

• G06F15/80

  comprising an array of processing units with common control, e.g. single instruction multiple data processors (G06F15/82 takes precedence {; for correlation function computation G06F17/15}) · CPC title

• G06N20/00 Primary

  Machine learning · CPC title

• G06F13/4068

  Electrical coupling · CPC title

• G06F13/36 Primary

  for access to common bus or bus system · CPC title

• G06N10/00

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