A quantum phenomenon where two or more qubits become correlated such that the state of one instantly determines the state of the others, regardless of distance — Einstein famously called it 'spooky action at a distance'.
Entangled qubits cannot be described independently — measuring one immediately collapses the others' states in correlated ways. Entanglement is created via two-qubit gates (CNOT, CZ) and is the resource that enables quantum algorithms to achieve speedups over classical alternatives. Without entanglement, n qubits would behave like n independent two-state systems with no quantum advantage. Quantum teleportation, dense coding, and quantum key distribution all rely on entanglement.
Creating a Bell-state pair of entangled qubits — measuring qubit A as 0 instantly determines qubit B is also 0, with 100% correlation across any distance.
Entanglement is the second pillar (after superposition) of quantum computational advantage — its proper use distinguishes useful quantum algorithms from naive ones.
Need help implementing this in your business?
Get Started