Hawkynt

CSS Quantum Code

Quantum stabilizer code constructed from two classical linear codes C1 and C2 where the dual of C2 is a subset of C1. Corrects quantum errors (bit-flip X and phase-flip Z errors). Steane [[7,1,3]] code corrects one qubit error. Foundation for fault-tolerant quantum computing. Used in quantum computers by IBM, Google.

Properties

Property Value
Category Error Correction
Sub-category Quantum Code
Security status πŸŽ“ Educational Only
Complexity Expert
Inventor Robert Calderbank, Peter Shor, Andrew Steane
Year 1996
Origin πŸ‡ΊπŸ‡Έ United States
Source algorithms/ecc/css-quantum-code.js

Security

Status: πŸŽ“ Educational Only

Known vulnerabilities

Issue Description Mitigation
Single Qubit Error Correction Only Steane [[7,1,3]] code can only correct 1 arbitrary qubit error (bit-flip, phase-flip, or both). Multiple errors cause decoding failure. β€”
Overhead Cost Encodes 1 logical qubit into 7 physical qubits (7x overhead). Higher-distance CSS codes have even larger overhead. β€”
Classical Simulation Limitations This implementation treats quantum states as classical bit arrays for educational purposes. Real quantum error correction requires quantum hardware and preserves superposition states. β€”
Measurement Errors Does not account for measurement errors in syndrome extraction, which real quantum systems must address through fault-tolerant protocols. β€”

Documentation

References

Test vectors

2 vectors ship with this algorithm and run in the test suite. Byte values are hexadecimal.

Vector 1 β€” Steane [[7,1,3]] encode logical qubit state 0

Field Value
input 00
expected 00000000000000

Vector 2 β€” Steane [[7,1,3]] encode logical qubit state 1

Field Value
input 01
expected 01010101010101

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