Apparatus and method for quantum error correction without measurement or active feedback

Patent metadata

Field	Value
Publication number	US-11907808-B2
Application number	US-202117464583-A
Country	US
Kind code	B2
Filing date	Sep 1, 2021
Priority date	Sep 1, 2021
Publication date	Feb 20, 2024
Grant date	Feb 20, 2024

Abstract

Apparatus and method for measurement-free (MF) quantum error correction (QEC). For example, one embodiment of a method comprises: determining an error syndrome on a first subset of ancilla qubits of a quantum processor; decoding the error syndrome to produce decoded results on a second subset of ancilla qubits of the quantum processor; applying the decoded results to one or more system qubits; and unconditionally resetting the first subset and/or second subset of ancilla qubits to remove entropy and/or noise from the quantum system, wherein the operations of determining the error syndrome, decoding the error syndrome, applying the error syndrome, and unconditionally resetting the first and/or second subset of ancilla qubits are performed responsive to a qubit controller executing quantum control instructions provided from or derived from a script and without transmitting measurement data related to the error syndrome to a non-quantum computing device.

First claim

What is claimed is:

1. A method comprising:
determining an error syndrome on a first subset of ancilla qubits of a quantum processor;
decoding the error syndrome to produce decoded results on a second subset of ancilla qubits of the quantum processor;
applying the decoded results to one or more system qubits; and
unconditionally resetting the first subset and/or second subset of ancilla qubits to remove entropy and/or noise from the quantum system,
wherein the operations of determining the error syndrome, decoding the error syndrome, applying the decoding results, and unconditionally resetting the first and/or second subset of ancilla qubits are performed responsive to a qubit controller executing quantum control instructions provided from or derived from a script and without transmitting measurement data related to the error syndrome to a non-quantum computing device.

2. The method of claim 1 wherein the script specifies a sequence of quantum operations which are translated by a compiler to generate the quantum control instructions.

3. The method of claim 2 wherein the operation of unconditionally resetting the first and/or second subset of ancilla qubits is performed by the qubit controller, responsive to at least one of the quantum control instructions.

4. The method of claim 3 wherein the operations of determining the error syndrome, decoding the error syndrome, and applying the decoding results are performed by the qubit controller, responsive to at least one of the quantum control instructions.

5. The method of claim 4 wherein, responsive to the quantum control instructions, the qubit controller is to generate a first set of one or more pulses to perform the operations of determining the error syndrome, decoding the error syndrome, and applying the decoding results.

6. The method of claim 5 wherein, responsive to the at least one quantum control instruction, the qubit controller is to generate a second set of one or more pulses to perform the operation of unconditionally resetting the first and/or second subset of ancilla qubits.

7. The method of claim 1 wherein determining the error syndrome comprises either:
extracting the Z-stabilizer syndrome, wherein decoding the error syndrome comprises decoding the Z-stabilizer syndrome into an X-type unitary correction, or
extracting the X-stabilizer syndrome, wherein decoding the error syndrome comprises decoding the X-stabilizer syndrome into a Z-type unitary correction.

8. The method of claim 7 wherein extracting the Z-stabilizer syndrome or X-stabilizer syndrome comprises applying a sequence of unitary Clifford gates between the one or more system qubits and one or more of the ancilla qubits.

9. The method of claim 7 wherein applying the decoded results comprises applying the X-type unitary or Z-type unitary to the one or more system qubits and the first and second subsets of ancilla qubits.

10. An apparatus comprising:
a quantum processor comprising a plurality of qubits;
a quantum controller to autonomously execute a quantum error correction script to perform the operations of:
determining an error syndrome on a first subset of ancilla qubits of a quantum processor;
decoding the error syndrome to produce decoded results on a second subset of ancilla qubits of the quantum processor;
applying the decoded results to one or more system qubits; and
unconditionally resetting the first subset and/or second subset of ancilla qubits to remove entropy and/or noise from the quantum system,
wherein the operations of determining the error syndrome, decoding the error syndrome, applying the decoding results, and unconditionally resetting the first and/or second subset of ancilla qubits are performed responsive to a qubit controller executing quantum control instructions provided from or derived from a script and without transmitting measurement data related to the error syndrome to a non-quantum computing device.

11. The apparatus of claim 10 wherein the script specifies a sequence of quantum operations which are translated by a compiler to generate the quantum control instructions.

12. The apparatus of claim 11 wherein the operation of unconditionally resetting the first and/or second subset of ancilla qubits is performed by the qubit controller.

13. The apparatus of claim 12 wherein the operations of determining the error syndrome, decoding the error syndrome, and applying the decoding results are performed by the qubit controller, responsive to at least one of the quantum control instructions.

14. The apparatus of claim 13 wherein, responsive to the quantum control instructions, the qubit controller is to generate a first set of one or more pulses to perform the operations of determining the error syndrome, decoding the error syndrome, and applying the decoding results.

15. The apparatus of claim 14 wherein, responsive to the at least one instruction, the qubit controller is to generate a second set of one or more pulses to perform the operation of unconditionally resetting the first and/or second subset of ancilla qubits.

16. The apparatus of claim 10 wherein determining the error syndrome comprises either:
extracting the Z-stabilizer syndrome and wherein decoding the error syndrome comprises decoding the Z-stabilizer syndrome into an X-type unitary correction, or
extracting the X-stabilizer syndrome and wherein decoding the error syndrome comprises decoding the X-stabilizer syndrome into a Z-type unitary correction.

17. The apparatus of claim 16 wherein extracting the Z-stabilizer syndrome or X-stabilizer syndrome comprises applying a sequence of unitary Clifford gates between the one or more system qubits and one or more of the ancilla qubits.

18. The apparatus of claim 16 wherein applying the decoded results comprises applying the X-type unitary or Z-type unitary to the one or more system qubits and the first and second subsets of ancilla qubits.

19. A machine-readable medium having program code stored thereon which, when executed by a qubit controller, causes the operations of:
determining an error syndrome on a first subset of ancilla qubits of a quantum processor;
decoding the error syndrome to produce decoded results on a second subset of ancilla qubits of the quantum processor;
applying the decoded results to one or more system qubits; and
unconditionally resetting the first subset and/or second subset of ancilla qubits to remove entropy and/or noise from the quantum system,
wherein the operations of determining the error syndrome, decoding the error syndrome, applying the decoding results, and unconditionally resetting the first and/or second subset of ancilla qubits are performed responsive to a qubit controller executing quantum control instructions provided from or derived from a script and without transmitting measurement data related to the error syndrome to a non-quantum computing device.

20. The machine-readable medium of claim 19 wherein the script specifies a sequence of quantum operations which are translated by a compiler to generate the quantum control instructions.

21. The machine-readable medium of claim 20 wherein the operation of unconditionally resetting the first and/or second subset of ancilla qubits is performed by the qubit controller.

22. The machine-readable medium of claim 21 wherein the operations of determining the error syndrome, decoding the error syndrome, and applying the decoding results are performed by the qubit controller, responsive to at least one of

Assignees

• Intel Corp

Inventors

• Schmitz Albert
• Matsuura Anne
• Pillarisetty Ravi
• Premaratne Shavindra
• Hogaboam Justin
• Lampert Lester

Classifications

• G06N10/40

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

• G06N10/20

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

• G06N10/80

  Quantum programming, e.g. interfaces, languages or software-development kits for creating or handling programs capable of running on quantum computers; Platforms for simulating or accessing quantum computers, e.g. cloud-based quantum computing · CPC title

• B82Y10/00

  Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic · CPC title

• G06N10/70 Primary

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