Recent content by DrChinese

Greene says the 5/9 number (55%) at that point and associates it with the EPR view* that properties must be well-defined prior to measurement. Brian is extrapolating a point, and if we are not careful, we will be referring to differences that merely result from labeling. At the time of EPR...

You must not mix trials in which the selected axes are the same for Alice and Bob with those where those axes are different. The quantum expectation is completely different. Apples and oranges.

1. As quoted from EPR above: The position of QM: "...since either one or the other, but not both simultaneously, of the [non-commuting] quantities P and Q can be predicted, they are not simultaneously real...This makes the reality of P and Q depend upon the process of measurement carried out on...

As several have already pointed out, we don't have a quantum theory of gravity to guide us on this point. More importantly: there is absolutely no requirement that our current theory of gravity - General Relativity - needs to be updated to be a quantum theory. There have been papers on the...

Agreeing 100% with everything that @PeterDonis is saying: EPR said that *any* observable of Bob could be predicted with certainty by an appropriate measurement on Alice. They deducted (as have you) that Bob's observables must be predetermined (they did not use those words) and therefore QM was...

An entangled photon will behave as what you call “normal” and will produce the usual interference pattern if you place a single slit in front of the double slits. That creates a coherent state and stops the entanglement for that photon. But… don’t think that means the other photon will evidence...

Entangled photons do not produce traditional interference patterns in the manner you imagine. It’s not possible to explain it without a sufficiently detailed example, but the short story is that such photons do not self interfere and they don’t interfere with each other. However, 2 different...

Actually you would see the 2 outcomes as correlated, momentum conserved if they went in opposite directions. There would simply be no interference pattern formed as more and more were observed.

Imagine you send an entangled particle though a double slit. It simply will not produce the expected interference pattern. The reasons are a bit complicated, but entangled particles are not coherent. See figure 2 of the following, along with the related text. Written by one of the premier...

The simple answer has already been presented. Entangled particle pairs - whether electrons or photons- generally do not exhibit single particle self-interference. For them to do that, the entanglement must cease on the appropriate basis. I’m sure you realize that were that not true, FTL...

It's Mr. DrChinese. Note that I am not a doctor of any kind that involves a degree. My musician friends simply call me Doc, so that's good as well. We're all friends here. :smile: Oh, and I am not Chinese (according to 23 and me).

1. Agree, that's true in all swapping setups. The experiment consists of having another distant scientist who makes a decision to entangle - or not - the 1 & 4 photons. Of course, she must his report her results just as Alice and Bob do. I wouldn't call requiring the results of distant...

Not an answer to your question, but an interesting fact: those entangled photons need not be of identical wavelength. In fact, you can even use photons to entangle (via swapping) spins of 2 distant electrons. In principle, there is no requirement that the particle types even be the same...

1. Yes, it's true that the results of 3 distant observers must be brought together to demonstrate nonlocality. That would always be true in demonstrating quantum nonlocality*. So if that is your "out", it's circular reasoning. There is no meaningful filtering occurring, in the sense that some...

1. There are 2 subsets of 4 fold entangled coincidences that are relevant (all within the appropriate time window): ψ+ and ψ-. The only "filtering" is the requirement of 4 fold coincidences. Note that there are 4 Bell states, but only 2 of the 4 can be identified in most experiments. The other...