Wikipedia:Reference desk/Archives/Science/2021 February 28

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February 28

Question about a particular deadly condition for old people

What is the condition called where an old person's blood circulation stops working properly and this old person begins needing blood thinner and this old person's various organs and body parts also gradually begin to give out as a result of their poor blood circulation? Futurist110 (talk) 05:27, 28 February 2021 (UTC)

Are you talking about Congestive heart failure? ←Baseball Bugs ^{What's up, Doc?} carrots→ 06:01, 28 February 2021 (UTC)

Probably Atherosclerosis.--Wikimedes (talk) 07:19, 28 February 2021 (UTC)

Or perhaps Peripheral artery disease? If properly treated (possibly including a change in lifestyle), the prognosis is not particularly bad, though. Poor blood circulation can arise as a result of several medical conditions, including (obviously) the already mentioned congestive heart failure, which in turn can have a variety of underlying causes. While statins may be prescribed, they are not blood thinners. Blood thinners may be prescribed if the underlying cause is coronary artery disease – not so much to improve circulation, but specifically to counter the formation of blood clots in the coronary arteries.  --Lambiam 08:18, 28 February 2021 (UTC)

Quantum Entanglement

I am clearly getting in the area where I don't belong, however, the issue bothers me. A couple of years ago an experiment was conducted to prove the quantum entanglement "once and for all." I first ran into the description in the Amazon documentary "Einstein's quantum puzzle" or similar. It is in their Prime Video section. Then there are two descriptions, one by the Austrians [1] who did the experiment, the other by MIT people [2]. The Prime Video channel provides a nice animated diagram, very helpful. In short, they needed two random numbers generators that must be totally independent. They found them in signals from two quasars on opposite sides of the sky, as they said in the opposite sides of the Universe. The distances to the quasars were enormous. They have their reasoning about it, which you can read there. The problem is that they say that those two quasars, to have been created in a very young Universe, never shook hands with one another physically because of the enormous distance between them. They implicitly assume that the history of quasars began at the time of their creation.

I don't think it is correct. In the very early Universe in the first billionth of a second or so there were quantum fluctuations that deformed the universe or perhaps parts thereof which eventually resulted in appearance of those two quasars. It is possible that both areas which much later became those quasars were subjected to the same pressure fluctuations because of the small size of the Universe at that time.

I also can offer a solution for the random number generators for this experiment. They got the computer numbers by some conversion of light signals which are constantly in a flux. They should have selected a small sequence of numbers e.g. 100 from one quasar and tried to find a match (or better a simple correlation) of this sequel in another quasar. Then they had to do such comparison with a slightly larger sequence, perhaps 110 numbers from the first quasar, etc. After repeating this numerous times they could prove total independence of the sources.

I wonder it all makes sense? AboutFace 22 (talk) 21:19, 28 February 2021 (UTC)

You're asking good questions. Bell's inequalities rely on a "no-conspiracies" assumption that's difficult to pin down exactly. See [3], [4] for some discussion. The version of the experiment that uses quasars as a source of random numbers can't completely eliminate this loophole. However, it can say that the "conspiracy" that could fool you would have to be on the scale of the entire universe and lasting many billions of years. From an MIT press release [5]:

“If some conspiracy is happening to simulate quantum mechanics by a mechanism that is actually classical, that mechanism would have had to begin its operations — somehow knowing exactly when, where, and how this experiment was going to be done — at least 7.8 billion years ago. That seems incredibly implausible, so we have very strong evidence that quantum mechanics is the right explanation,” says co-author Alan Guth, the Victor F. Weisskopf Professor of Physics at MIT.

The version you describe, going back to the quantum fluctuations that seeded the structures that went on to form the quasars, is something like superdeterminism. It may be impossible even in principle to rule this out. Your idea about comparing 100 random numbers doesn't help, because the kind of correlation relevant to the Bell-type experiment is a three-way one that would involve the two quasars and the experimental results on Earth. It would not necessarily produce a correlation between the two quasars alone that could be detected by any possible statistical test. --Amble (talk) 18:19, 1 March 2021 (UTC)

A little more about looking for correlations in the quasar signals... No statistical test of the quasar signals could eliminate the loophole, even in principle. That’s because it’s not about whether the quasar signals themselves are correlated. They could be perfectly good, completely independent random numbers. The loophole is about whether the experimental apparatus on Earth and the entangled particles could somehow already “know” those numbers before they arrive. It’s like a one-time pad in cryptography. There is no test you can perform on the secret key that can tell you whether your enemy has somehow managed to get a copy. —Amble (talk) 17:01, 2 March 2021 (UTC)

Slightly off-topic AboutFace 22 but I think you will be interested in the Free will theorem article, if you are not already aware of it. There is a fascinating set of 6 lectures by Conway (linked at the bottom of the article) which cover this related subject in detail and in an entertaining way (IMHO). Mike Turnbull (talk) 13:42, 6 March 2021 (UTC)