Skip to main content
Glossary

Quantum glossary

GHZ state

Also: greenberger horne zeilinger, cat state

An entangled state of three or more qubits that are all 0 or all 1, in superposition.

Lose any one qubit and the entanglement of the rest is destroyed, which makes GHZ states fragile — and a common benchmark of how well a device preserves multi-qubit coherence.

(|000⟩ + |111⟩)/√2

See it for yourself

Related terms

  • Entanglement — A correlation between quantum systems so strong that the whole has a definite state while the parts do not.
  • Bell state — One of four maximally entangled two-qubit states; the simplest and most-used form of entanglement.