Quantum Error Correction Decoding with Ball-Growing Clusters

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Solution Overview

Problem

Decoding quantum error correction codes in quantum computers is a critical process that needs to be performed quickly to handle the high-speed flow of error correction data, but existing decoders like Union-Find are too slow for real-time processing.

Innovation Solution

A new data structure and method for decoding syndromes using a Clustering Union-Find approach, where each defect is surrounded by a ball with an iteratively increasing radius, allowing efficient clustering of syndrome qubits into even-numbered clusters for decoding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If existing decoders like Union-Find are used to decode quantum error correction codes, then decoding accuracy is maintained, but decoding speed is too slow for real-time processing

Engineering Contradiction:
Improvedecoding speedVSAvoidprocessing time
Core Design Contradiction:
SpeedVSLoss of time

Solution Approach 1:

The patent segments the decoding process into distinct phases: syndrome processing to identify defects, recording defect locations in a data structure, and iteratively determining ball radii by growing clusters. This segmentation allows each phase to be optimized independently, with the ball-growing approach enabling faster cluster formation compared to traditional Union-Find methods while maintaining decoding accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary actions by pre-establishing the data structure to record defect locations and pre-defining the ball-growing algorithm framework before actual decoding occurs. The iterative radius determination process is prepared in advance with clear termination conditions (when balls touch or overlap), enabling rapid execution during real-time decoding without computational overhead.

Inventive Principle:
Principle #10Preliminary action

2Quantity of substance

If traditional decoding methods are used, then decoding completeness is achieved, but memory requirements are excessive

Engineering Contradiction:
Improvememory usageVSAvoiddecoding completeness
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent extracts only the essential information needed for decoding by recording solely defect locations and ball radii in the data structure, rather than storing complete syndrome information or intermediate computational states. This extraction approach reduces memory requirements while maintaining decoding completeness, as the ball-growing algorithm can reconstruct all necessary cluster information from these compact representations.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of building up complete cluster information incrementally as in traditional Union-Find methods, the patent inverts the approach by starting with individual defect locations and growing balls outward until they touch or overlap. This inversion allows the system to determine cluster boundaries efficiently without storing extensive intermediate data, reducing memory usage while achieving complete decoding.

Inventive Principle:
Principle #13The other way round (Inversion)

3Measurement precision

If ball radius is increased to ensure complete cluster coverage, then decoding accuracy improves, but computational complexity increases

Engineering Contradiction:
Improvecluster identification accuracyVSAvoidalgorithm complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the ball radius a variable that grows iteratively rather than a fixed parameter. The radius increases step-by-step until termination conditions are met (balls touch or overlap), allowing the system to adapt the coverage extent to the actual spatial distribution of defects. This dynamic approach ensures complete cluster coverage when needed while avoiding unnecessary computational complexity when defects are naturally well-separated.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent incorporates feedback through the iterative radius determination process, where each radius increase is evaluated against termination conditions (whether balls touch or overlap with other balls). This feedback mechanism automatically adjusts the ball radius to the minimum necessary value for accurate cluster identification, preventing excessive radius growth that would increase computational complexity without improving accuracy.

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS12462183B2Decoding quantum error correction codes
Publication Date: 2025.11.04 RIVERLANE LTD
  • US12462183B2 patent drawing
  • US12462183B2 patent drawing
  • US12462183B2 patent drawing

AI summary

A computer-implemented method for use in decoding syndromes of a quantum error correction code, the syndromes comprising measurement data from a quantum computer comprising a plurality of syndrome qubits and a plurality of data qubits. The method comprises: processing the syndromes to identify defects; recording, in a data structure, respective locations for each defect; and determining a respective radius, for each respective defect, of a ball surrounding the respective location of the respective defect, and recording each respective radius with its respective location in the data structure, wherein each respective radius is determined by iteratively increasing a length of the respective radius until each respective radius defines a ball touching or overlapping at least one other ball surrounding another of the respective locations, such that each respective location belongs to a cluster consisting of an even number of the locations of the defects; wherein the data structure thereby enables decoding of the quantum error correction code.