Quantum Entanglement
A quantum phenomenon in which two or more particles become interconnected such that the quantum state of each particle cannot be described independently of the others.
Governing formula
|Ψ⟩ = (1 / √2) (|0⟩|1⟩ - |1⟩|0⟩)
SI unit
Dimensionless Quantum State
In depth
Entangled particles exhibit non-local state correlations regardless of spatial separation. Measuring an observable property (e.g. spin component) of one entangled particle instantly determines the corresponding property of its partner particle, violating classical local realism as confirmed by Bell test experiments.
Examples in the real world
Spontaneous parametric down-conversion creating entangled photon pairs used in quantum cryptography and quantum teleportation protocols.