Quantum Entanglement
Correlations without communication — what Bell tests established and what they did not.
Entanglement
What is entanglement?
Entanglement is a link between quantum systems in which the whole has a definite description while its parts do not.
Entangled systems show correlations stronger than any classical shared-instruction model allows, as confirmed by Bell tests.
Entanglement is a resource for teleportation, quantum key distribution, and quantum networking — but it cannot transmit a message on its own.
Recommended learning sequence
- Quantum EntanglementCorrelations without communication — what Bell tests established and what they did not.
Frequently asked questions
- What is quantum entanglement?
- A quantum link producing correlations between systems that no classical model can reproduce, with random-looking results locally.
- Can entanglement be used to communicate faster than light?
- No. Local outcomes are random; a classical channel is always required.
Lessons in this topic
Related subjects
Quantum Teleportation
Quantum teleportation transfers a quantum state between locations using shared entanglement and two classical bits.
Quantum Communication
Quantum communication transmits quantum states between locations, usually encoded in photons over fibre or free space.
Superposition
Superposition is a quantum state formed by combining other states, each carrying an amplitude.