A What does the first ever photo of quantum entanglement look like?

[Tom.G]

A photo:
https://petapixel.com/assets/uploads/2019/07/quantum.jpg
The popular press version (with above photo):
https://petapixel.com/2019/07/13/this-is-the-first-ever-photo-of-quantum-entanglement/
The full paper in Science Magazine:
https://advances.sciencemag.org/content/5/7/eaaw2563

 

[bhobba]

From the paper:
'Because we do not close all the various loopholes, our demonstration cannot be interpreted as another absolute demonstration that the world is behaving in a nonlocal way.'

I wish referees would do a better job. It really would make reading them a lot easier. To be fair Einstein's early papers were full of errors not picked up by referees so it's far from a new phenomena.

There is no proof of non-locality in QM. All Bell, and its experimental confirmation, shows is a non-classical statistical correlation. What it means is simply QM is not a classical probability model - its a generalized probability model. Want it to be one - then you need non-local influences. But the world may simply not be classical in its statistical behavior - it does not have to be non-local.

See:
https://arxiv.org/abs/1402.6562
Thanks
Bill

 

[vanhees71]

Can you point to the many errors in Einstein's early papers? There are astonishingly few, if you ask me, given that particularly the early papers (including the 3-4 ones in his annus mirabilis) were about groundbreaking new ideas like relativity, early quantum theory of light, and statistical physics. Of course, ironically the only theory that's obsolete is the very one Einstein got the Nobel prize for (because the Nobel Committee had not the guts to see that Bergson is a completely irrelevant figure providing nonsensical gibberish about the nature of time, and thus didn't dare to give Einstein the Nobel for his greatest achievement, which was GR).

The other point is that at this time there was no peer reviewing in the modern sense. The papers sent to a journal was accepted by an editor of this journal. In these days for Annalen der Physik this was among others Planck.

When Einstein first published in Phys. Rev. he was furious when he got a referee report (nowdays we know it was most probably Robertson) about a paper proving the non-existence of gravitational waves in GR. He took it as very bad that the editor of the journal has given the contents of his article to somebody else before publication ;-)). BTW, Robertson was right in his criticism.

https://physicstoday.scitation.org/doi/full/10.1063/1.2117822

 

[Michael Price]

Of course, ironically the only theory that's obsolete is the very one Einstein got the Nobel prize for (because the Nobel Committee had not the guts to see that Bergson is a completely irrelevant figure providing nonsensical gibberish about the nature of time, and thus didn't dare to give Einstein the Nobel for his greatest achievement, which was GR).

I guess this is Henri Bergson, who I'd never heard of before. Yes, sounds like gibberish. ☺
https://en.m.wikipedia.org/wiki/Henri_Bergson

 

[vanhees71]

A very detailed book is this:

https://www.amazon.com/dp/0691165343/?tag=pfamazon01-20

Though trying hard, to be honest, I couldn't even figure out, what Bergson's idea about time is really about.

 

[msumm21]

There is no proof of non-locality in QM. All Bell, and its experimental confirmation, shows is a non-classical statistical correlation. What it means is simply QM is not a classical probability model - its a generalized probability model. Want it to be one - then you need non-local influences. But the world may simply not be classical in its statistical behavior - it does not have to be non-local.

Is there an easy explanation of how a non-classical correlation works, e.g. in the case of spin entangled Bell violations? It can make sense with only local influences? Without assuming determinism or many-worlds?

 

[Mentz114]

Can you point to the many errors in Einstein's early papers? There are astonishingly few, if you ask me, given that particularly the early papers (including the 3-4 ones in his annus mirabilis) were about groundbreaking new ideas like relativity, early quantum theory of light, and statistical physics. Of course, ironically the only theory that's obsolete is the very one Einstein got the Nobel prize for (because the Nobel Committee had not the guts to see that Bergson is a completely irrelevant figure providing nonsensical gibberish about the nature of time, and thus didn't dare to give Einstein the Nobel for his greatest achievement, which was GR).

The other point is that at this time there was no peer reviewing in the modern sense. The papers sent to a journal was accepted by an editor of this journal. In these days for Annalen der Physik this was among others Planck.

When Einstein first published in Phys. Rev. he was furious when he got a referee report (nowdays we know it was most probably Robertson) about a paper proving the non-existence of gravitational waves in GR. He took it as very bad that the editor of the journal has given the contents of his article to somebody else before publication ;-)). BTW, Robertson was right in his criticism.

https://physicstoday.scitation.org/doi/full/10.1063/1.2117822

Absolutely. Einstein earned at least 2 Nobel prizes - SR in conjunction with others and GR ( which is probably worth 2 !

 

[PeterDonis]

Einstein earned at least 2 Nobel prizes - SR in conjunction with others and GR

I assume you mean "earned but never actually got", since the only Nobel Prize Einstein was awarded (the 1921 physics one) was "for his services to Theoretical Physics, and especially for his discovery of the law of the photoelectric effect." No mention of SR or GR (and that was intentional since the Nobel committee still thought those theories were too radical to base a prize on).

 

[forcefield]

See:
https://arxiv.org/abs/1402.6562

I hesitate to contribute to an advanced thread but their definition of "realism" in the context of what Bell proved does not seem to be right. This is what they say: "A theory obeys realism if measurement outcomes can be interpreted as revealing a property of the system that exists independent of the measurement". Didn't Bell rather prove something about any properties of the system leading to correct predictions (and nothing about whether those properties are revealed by the measurement)?

 

[vanhees71]

The point is that Bell defined a general class of local hidden variable theories that are "realistic" in this sense, i.e., deterministic, meaning that all observables of a system always has determined values which are simply revealed by measuring them.

In contradistinction to that the probabilistic interpretation of the quantum state a la Born implies that this cannot be the right idea of "realism". There only those observables take determined values if the system is prepared in a corresponding state (if it's a pure state this is given by an eigenvector of the observable operator to the corresponding eigenvalue). All other observables do not have definite values, but (precise) measurements yield one of the possible values with a probaility (distribution) given by the state it is prepared in.

Bell's class of local realistic HV models imply an inequality for certain correlation functions of spin measurements, which are predicted by QT to be violated in some cases. This made the question about "realism" in this particular sense a clear scientific question which can be decided (at the time only in principle) by scientific experiment, and quite soon indeed these experiments could be done and ruled out any local realistic HV theory while QT was confirmed.

 

[Mentz114]

I assume you mean "earned but never actually got", since the only Nobel Prize Einstein was awarded (the 1921 physics one) was "for his services to Theoretical Physics, and especially for his discovery of the law of the photoelectric effect." No mention of SR or GR (and that was intentional since the Nobel committee still thought those theories were too radical to base a prize on).

Obviously - I'm complaining that he should have got more prizes.

 

[RUTA]

Is there an easy explanation of how a non-classical correlation works, e.g. in the case of spin entangled Bell violations? It can make sense with only local influences? Without assuming determinism or many-worlds?

Here is an explanation suitable for anyone who knows intro physics: https://arxiv.org/abs/1809.08231. In fact, I had several of my Honors students in intro physics read and comment on it before posting. Here is a generalized version just published in Entropy: https://www.mdpi.com/1099-4300/21/7/692/pdf. Here is the talk I gave on that paper: which is pretty basic.

The bottom line in all these is that contrary to popular myth, QM and SR are self-consistent as they are ultimately based on the same principle — no preferred reference frame. This explains the one difference between the quantum and classical joint distributions per Garg and Mermin (see citation in either paper), i.e., that Bob and Alice both always measure +1/-1 regardless of their reference frame. That fact alone then accounts for the “weird” QM correlation just like the light postulate accounts for the “weird” relativity of simultaneity in SR. In other words, what people find so weird about modern physics is due to the fact that no one’s sense experiences can provide a favored perspective on the real external world (to borrow from Einstein). Specifically here wrt the measurements of fundamental constants (c and h).

 

[vanhees71]

The Nobel committee even emphasized on the Nobel certificate that the prize is explicitly not for relativity. Unfortunately I couldn't find a fully readable scan of the certificate yet, but only secondary sources:

The Nobel citation reads that Einstein is honoured for "services to theoretical physics, and especially for his discovery of the law of the photoelectric effect". At first glance, the reference to theoretical physics could have been a back door through which the committee acknowledged relativity. However, there was a caveat stating that the award was presented "without taking into account the value that will be accorded your relativity and gravitation theories after these are confirmed in the future".

from:

https://www.theguardian.com/science/across-the-universe/2012/oct/08/einstein-nobel-prize-relativity

 

[bhobba]

Can you point to the many errors in Einstein's early papers?

I got it from the following book:
https://www.amazon.com/dp/0393337685/?tag=pfamazon01-20

I can dig up the page where he mentions the book on his collected early works had a huge amount of footnotes correcting errors. The one I remember he went on about was clock syncing by slow transport - Einstein evidently, at least initially, did not consider it.

To be fair I have Ohanian's GR textbook (it was the first serious book I read on GR) and its pretty obvious, from even that book, he thinks Einstein made quite a few errors. He even based his whole approach to GR not on how Einstein did it because he has issues with the principle of equivalence - he thinks that you can't ever get rid of tidal effects invalidates it. I personally do not agree - but its his view:
https://hep.physics.utoronto.ca/~pekka/phy140y/lectures/Lecture_6.pdf
He used Field Theory and analogy with EM instead. He called him a 'sleepwalker' - he knew where he wanted to go, and was correct, but how he did it was 'iffy' eg objections from Kretschmann that even in modern times is still discussed:
https://www.pitt.edu/~jdnorton/papers/NortonGCGTKO.pdf
Ohanian wrote a paper on Einsteins mistakes in E=MC^2:
https://arxiv.org/ftp/arxiv/papers/0805/0805.1400.pdf
Added Later:
Whoops I accidentally gave the same link as before.

My personal view - its a hobby horse of Ohanian - technically correct but in no way detracts from Einstein or his accomplishments.

Thanks
Bill

 

[sysprog]

QM and SR are self-consistent as they are ultimately based on the same principle — no preferred reference frame.

Presumably you meant (not only self-consistent but also) inter-consistent.

 

[member 648030]

A photo:
https://petapixel.com/assets/uploads/2019/07/quantum.jpg
The popular press version (with above photo):
https://petapixel.com/2019/07/13/this-is-the-first-ever-photo-of-quantum-entanglement/
The full paper in Science Magazine:
https://advances.sciencemag.org/content/5/7/eaaw2563

very intersting

 

[Dale]

Temporarily closed for moderation.

Edit: thread reopened. Several posts on non-physics based “theories” of time have been removed. Also, please note that the discussion about Einstein’s Nobel prize is not particularly relevant to the OP. I am not removing it, but just recommending that such discussion be taken to a different thread if desired. Perhaps in the general discussion forum.