Recent content by Morbert

I responded to that in post post #201 https://www.physicsforums.com/threads/entanglement-swapping-and-bohmian-mechanics.1086070/post-7320927 I just want this point to be clear. You are saying that while Ma's physics is right, he misspoke when he said (2) is a rewriting of (1)?

Ma explicitly says (2) is a rewriting of (1) in the basis of Bell states of photons 2 and 3. Did he misspeak?

Equation (2) does not present photon 2 and 3 in a Bell state. It instead shows the initial state expanded in a Bell basis. An analogous mistake would be @Morbert : "I have `2 + 2` dollars." @DrChinese : "No you don't! You have `4` dollars!"

@DrChinese is unfortunately caught in a closed loop where he will deny this QM math based on his misreading of Ma's paper, and his misreading of Ma's paper is based on his misunderstanding of QM math.

So you're saying Ma's physics is right and he just misspoke? When he said "This can be seen by rewriting Eq. (1) in the basis of Bell states of photons 2 and 3", he misspoke, as (2) is not in fact a rewriting of (1)?

Photons 2 and 3 are not initially entangled, as can be seen by tracing 1 and 4 out of the initial state (equation (1), or equation (2), which is a rewriting of (1)). @DrChinese is misreading (2) as a state where 2 and 3 and entangled. Instead it's the initial state, where 2 and 3 are not entangled.

So you're saying that, when Ma says "This can be seen by rewriting Eq. (1) in the basis of Bell states of photons 2 and 3" yielding (2), he's wrong?

"This can be seen by rewriting Eq. (1) in the basis of Bell states of photons 2 and 3" -- Ma Ma says (1) can be written in the basis of Bell states of photons 2 and 3. You are misreading this as Ma saying (2) is the quantum state post-measurement.

👍fixed

Show me where Ma says that. You'll find it difficult since Ma explicitly says [1] can be rewritten as [2]. You're presenting your basic algebra mistakes [edit] as Ma's. What's frustrating is these are precisely the same mistakes you were making in earlier threads. No progress has been made.

If it was the latter there would be no minus signs.

What you mean to say is $$\begin{aligned} |\Psi^{-}\rangle\langle\Psi^{-}|_{12} \otimes |\Psi^{-}\rangle\langle\Psi^{-}|_{34} \neq \frac{1}{4}\Big( &|\Psi^{+}\rangle\langle\Psi^{+}|_{14} \otimes |\Psi^{+}\rangle\langle\Psi^{+}|_{23}+ |\Psi^{-}\rangle\langle\Psi^{-}|_{14} \otimes...

PS to tie my last post to Bohmian mechanics you could presumably include detector and environmental degrees of freedom so the states becomes a pure states and hence pilot waves for the total system's trajectory.

As the conversation has continued I'll post here. In Ma's actual experiment, the BiSA apparatus is interpreted as performing a measurement at the incoming spatial modes. I.e. the detector clicks that occur near modes b'' and c'' are interpreted as a measurement at the prior modes b and c. This...

I may save my responses to @PeterDonis for that thread as they are about the experiment in general rather than a Bohmian accounting.