#### Entanglement, Causality and Local Realism

I have been walking around with the notion that "quantum entanglement implies a causal relationship due to the states having a shared history". I am now not so

sure that even fits into any interpretation of QM. To be honest, I'm not even sure what I am saying as the whole subject seems to be just out of my reach.

When I talk about entanglement, I say that the preparation of the entangled state places information in the entangled state at the time of preparation and this "influences" future measurements. Where "this influences future measurements" in the last sentence I mean that the entangled states share a Hilbert space containing the eigenvectors of the joint Hamiltonian of the entangled objects. I'm not sure if I am way off course in my comprehension or if I have a problem with my language.

I would really appreciate some guidance on this.

## I have asked one of the

I have asked one of the heavy weights in QM foundations and he was nice enough to reply.

the short answer is NO, entanglement doesn't imply a shared history. So the rest of what I am thinking needs work.

I was referred to http://arxiv.org/abs/quant-ph/9904042.

I am still confused as to how to interpret causality in Quantum Theory? Is there a canonical notion of causality in QT? (This is beyond the naive notion or Websters definition).