Concept 40 of 42 · Quantum Phenomena and Applications

Quantum computing with topological codes

Logical quantum information can be stored nonlocally in stabilizer-code degrees of freedom.

01 / The mathematical statement
$$\bar X\bar Z=-\bar Z\bar X$$

What this means

Logical quantum information can be stored nonlocally in stabilizer-code degrees of freedom.

Deep dive: mathematical and physical mechanism

In surface codes, data qubits and repeated local parity checks detect error syndromes. Logical operators form extended strings or loops; increasing code distance raises the minimum number of physical faults needed for an undetectable logical error.

How it appears in quantum phenomena

Superconducting and other quantum processors investigate surface-code error correction.

Assumptions, caveats and limitations

Error correction requires repeated high-fidelity measurements and decoding; threshold depends on the noise model.

Connect the ideas

For context, see the Quantum Phenomena and Applications topic guide and the reading references.

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