Demystifier's latest activity

I think neither option quite follows. The future swap does not need to cause the earlier A/D outcomes, and the earlier outcomes do not...

It's common in consistent histories literature, where you are often chaining many projectors together. See e.g. equation (2) in...

I would say that the swap operation implies the A/D entanglement. The difference is that "implication" is logical rather than physical...

Just a minor notational nitpicking. Is this your own notation, or have you seen it somewhere else? Wouldn't it be more common to use the...

I think I understand it better now. Thank you for your patience! :smile: Let me explain further and tell me if I'm wrong. If many runs...

To explicitly model* the measurement of 2 and 3 first, we would include the apparatus degrees of freedom and trace over them...

One more point, that points to the core of the confusion. To decide whether a certain state in the Hilbert space ##{\cal H}## is...

If I have to choose one of those, I choose i). You cannot actually observe the A/D correlation before you do the swap. The data from...

I think now the real issue is this. If the interaction between B and C happens after the measurement of A and D, are A and D entangled...

@PeterDonis in the closed thread you ask me about a reference for the claim that the quantum potential is not considered fundamental in...

@PeterDonis you are right, the word "spurious" was not appropriate.

Is the word "spurious" really justified here? After all, when B and C come together just before ##t_2##, B is entangled with the A...

Note, though, that you have to do postselection of the data from the A and D measurements regardless of whether A and D are measured...

If you are carrying out the textbook standard QM calculation of unitary evolution -> measurement -> collapse (preparation) -> unitary...

There is no action to the past. Suppose that at time ##t_1## you measure A and D, and later at ##t_2>t_1## put B and C into the...