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Glossary

Quantum glossary

QAOA

Also: quantum approximate optimization algorithm

A variational algorithm for combinatorial optimisation that alternates a problem Hamiltonian with a mixing Hamiltonian.

Depth p controls the quality: as p grows it can in principle reach the optimum. Whether low-depth QAOA beats the best classical heuristics on practical problems is not established.

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Related terms

  • Variational quantum eigensolver — A hybrid algorithm that estimates a Hamiltonian’s ground-state energy by optimising a variational circuit.
  • Variational circuit — A circuit with tunable rotation angles that a classical optimiser adjusts to minimise a cost.
  • Hamiltonian — The operator for a system’s total energy; it determines how the state evolves in time.