Topological Outcome Codes for Clifford Circuit Fault Correction

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Solution Overview

Problem

Current methods for fault correction in Clifford circuits applied to qubit registers of quantum computers are inefficient, particularly when using lookup-table decoders or LDPC decoders, which are difficult to construct and incur significant runtime costs.

Innovation Solution

The method involves receiving circuit data for a Clifford circuit and additional data identifying measurements on a lattice, emitting an outcome code with error syndrome checks, and generating a topological outcome code with check operators for quantum-error correction using a topological decoder.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If lookup-table decoders or LDPC decoders are used for fault correction in Clifford circuits, then fault correction capability is achieved, but device complexity and runtime cost increase significantly

Engineering Contradiction:
Improvefault correction capabilityVSAvoiddecoder construction complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex decoder construction (lookup-table or LDPC decoder building processes) with a topological decoding approach that uses stabilizer measurements and syndrome extraction. Instead of constructing complex decoding tables or LDPC matrices, the system uses quantum stabilizer measurements to directly extract error syndromes and apply corrections based on topological properties of the code, thereby reducing device complexity while maintaining fault correction capability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If lookup-table decoders or LDPC decoders are used for fault correction in Clifford circuits, then fault correction capability is achieved, but runtime cost increases significantly

Engineering Contradiction:
Improvefault correction capabilityVSAvoiddecoder runtime cost
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent substitutes the time-consuming processes of lookup-table searching or LDPC decoding iterations with a topological decoding method that leverages the mathematical structure of stabilizer codes. The system performs stabilizer measurements to obtain syndromes, then uses topological properties to directly determine corrections, eliminating the need for complex iterative decoding or table lookups, thereby significantly reducing runtime cost while preserving fault correction capability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If topological decoders are used for quantum-error correction, then device complexity and runtime cost are reduced, but ease of operation may be affected

Engineering Contradiction:
Improvedecoder construction complexityVSAvoiddecoder operation simplicity
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The topological decoding system performs self-service by automatically extracting error syndromes through stabilizer measurements and applying corrections based on inherent topological properties of the code. The decoder does not require manual construction of lookup tables or iterative solving processes; instead, the mathematical structure of the stabilizer code itself provides the decoding mechanism, making the system easier to operate while maintaining low complexity.

Inventive Principle:
Principle #25Self-service

Data Source

PatentUS20250061369A1Topological outcome codes for clifford circuits
Publication Date: 2025.02.20 MICROSOFT TECHNOLOGY LICENSING LLC
  • US20250061369A1 patent drawing
  • US20250061369A1 patent drawing
  • US20250061369A1 patent drawing

AI summary

A method to correct a fault in the application of a Clifford circuit to a qubit register of a quantum computer comprises: (a) receiving circuit data defining the Clifford circuit; (b) receiving additional data identifying one or more measurements belonging to each of a plurality of faces of a lattice; (c) emitting an outcome code based on the circuit data, the outcome code including a series of outcome checks each corresponding to an anticipated error syndrome for the application of the Clifford circuit to the qubit register; and (d) emitting a topological outcome code based on the circuit data, the additional data, and the outcome code, the topological outcome code including a series of check operators that support quantum-error correction via a topological decoder, thereby enabling fault correction in the application of the Clifford circuit to the qubit register.