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Glossary

Quantum glossary

Noise

Also: quantum noise, gate error, depolarizing

Any unwanted process that disturbs a quantum computation: imperfect gates, decoherence, crosstalk, readout errors.

Noise is characterised by error rates per gate and per measurement. Two-qubit gates and readout typically dominate. Every result from real hardware carries its signature, which is why comparing against a noise model is part of reading one.

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Related terms

  • Decoherence — The loss of quantum behaviour as a system becomes entangled with its uncontrolled environment.
  • Error mitigation — Techniques that reduce the bias noise introduces into results, without the qubit overhead of full error correction.
  • Quantum error correction — Encoding quantum information redundantly so errors can be detected and fixed without measuring — and destroying — the data.