We also have established many times that the final 1&4 state is uncorrelated and unentangled.
The aim of these teams is just to verify the predictions of QM, nothing more. Your personal goal, which is different from the goal of these teams, is to somehow infer causal relationships from the...
It speaks for itself that you find standard science "ridiculous." There is no evidence that the BSM has any effect on 1&4. The correlation in the post-selected ensembles is spurious, as any statistician will tell you. The conditioning on a common effect (the BSM result) introduces non-causal...
Just to complete @vanhees71's correct calculation: In total we then get 4 such subensembles, depending on the measurement outcome:
$$\rho_1 = P_{|\Psi_{23}^{+} \rangle \otimes |\Psi_{14}^{+} \rangle}\quad\rho_2 = P_{|\Psi_{23}^{-} \rangle \otimes |\Psi_{14}^{-} \rangle}\quad\rho_3 =...
This is the whole problem. You take a step back and try to understand what is being discussed and confirm the calculations on your own before replying.
I'm talking about the state of the 1&4 subsystem, which is given by ##\rho_{14}=\mathrm{tr}_{23}\rho_{1234} = \frac 1 4 \mathbb 1\otimes\mathbb...
This is literally the exact thing we have been discussing all along. Each Bell states corresponds to one of the four subensembles we have been discussing the whole time. Nothing this paper changes anything about the discussing.
Nobody said that post-selection was cherry picking. Post-selection...
No, the full system is not entangled. I have provided a mathematical proof several times and you had the opportunity to point at the equality sign that you do not comply with. You didn't bother to do that. On the other hand, you never provided any calculation at all. System 1&4 is in the product...
There are 3 systems, B, C and D in the paper. It discusses a general setting. System B corresponds to the 2&3 system in our case and systems C and D correspond to systems 1 and 4 respectively.
The swap gate is a mathematical abstraction of the physical situation in entanglement swapping. It abstractly models the transition that we previously denoted by ##\rho_{1234,\text{before}}\rightarrow\rho_{1234,\text{after}}## in terms of a 4 qubit system. The paper applies to all such swapping...
Fine, if you want to study the more complicated situation, it just means that you are even less allowed to conclude causal relationships from the collected data. It means you need to to perform even more checks of the causal structure and take even more possible causal relationships into...
Let me try once more to explain the relationship between correlation and causation and how it applies to entanglement swapping:
Experimentally, we find that certain sets of data show correlation between spacelike separated variables ##A## and ##B##. In general though, correlation does not imply...
You are being imprecise on purpose here. Quantum non-locality means nothing more than the fact that Bell's inequality is violated. What you want to imply is that there are non-local cause and effect relationships. The broad consensus among physicists is that no non-local cause and effect...
I don't think the specific details are relevant. The point of the event ready signal is to select those events which can safely be assumed to be successful measurements. This doesn't add anything conceptually new to the analysis of the idealized experiment. You still have a full ensemble of...
Picking a subensemble is not a quantum mechanical process. It's performed by the experimenter on his computer. But what does that have to do with the fact that the 1&4 subsystem is in the state ##\frac 1 4\mathbb 1\otimes\mathbb 1##, both before and after the BSM?
This sentence is quite...
I'm talking about an idealized experiment here. The event-ready scheme is an experimental complication in real world experiments in order to avoid measurement errors. The event ready signal is not produced by the BSM, but at the time of preparation. If the event ready signal occurs, we know that...
Even if you take a subensemble of the initial full ensemble, then DrChinese's state after the BSM would be a subensemble of that subensemble, so they still can't be compared.