# Basic quantum entanglement question [duplicate]

Please consider commenting on this basic quantum entanglement question or point me to articles that may enhance my knowledge.

Does quantum entanglement only occur in pairs, or can three or more particles become entangled?

## marked as duplicate by fibonatic, Jim, ACuriousMind♦, Kyle Kanos, JamalSJan 28 '15 at 21:45

• Welcome to Physics.SE. It is much preferred to ask one question per post. This will actually help you get better answers. I would strongly recommend that you edit this question so that it asks just your first point, and then post the other two separately. – DanielSank Jan 28 '15 at 17:33
• Suggestion: it is much better if you ask one time one question. This packaged questions are bad. Reformulate this to 3 different, and independent questions, and ask them again. If you ask multiple questions, it is not a problem here. – peterh Jan 28 '15 at 17:33
• If you google for "three particles entangled", the second hit is physics.stackexchange.com/q/54366 – Norbert Schuch Jan 28 '15 at 18:33

Entanglement with more than two particles is allowed. Mathematically, you could write, for example, $$|\psi\rangle = a|111\rangle + b|000\rangle.$$ Here, if you measure particle 1 to be in the "0" state, then you know immediately what the entire wave function is after measurement.