DeepPractise
DeepPractise

Entanglement

A correlation structure where a joint quantum state cannot be factored into states of its subsystems.

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A two-qubit state is separable if it can be written as ∣ψ⟩=∣a⟩⊗∣b⟩|\psi\rangle = |a\rangle\otimes|b\rangle. If it cannot, it’s entangled.

Canonical example

The Bell state:

∣Φ+⟩=(∣00⟩+∣11⟩)/2.|\Phi^+\rangle = (|00\rangle + |11\rangle)/\sqrt{2}.
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