Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It's 100% free.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Is it possible that we have entanglement in different degrees of freedom of a singe particle. like spin and linear momentum .

share|cite|improve this question
I wish nobody had used the word "entaglement" in physics when it really means a "coherent functional dependence". Of course the QM solutions of the one particle state will have a coherent functional correlation with all the variables and quantum numbers entering the problem. – anna v Mar 12 '14 at 14:13

Even though you think of it as a single particle -- each of it's different properties like momentum, spin, etc (corresponding to each valid quantum number) sits in a Hilbert space of their own and the possible configurations of a particle sits in a tensor product of those Hilbert spaces.

$$\mathcal{H_{particle}} = \mathcal{H_{momentum}} \otimes \mathcal{H_{spin}} \otimes \ldots $$

Like any other case, when we have a state in some space which can be broken up into subsystems tensored together, we can talk about correlations in those subsystems. If those correlations are quantum mechanical, then of course we will have entanglement -- like any other system you know about.

share|cite|improve this answer

Yes it is possible and in fact such states also have a fully classical description (coherence theory). Due to this fact this type of coherence is sometimes refered to as "classical entanglement."

share|cite|improve this answer

Yes, we can have entanglement between different degree of freedom of same particle or system. That is known as ''hybrid entanglement'' and that is experimentally demonstrated also.

share|cite|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.