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Nuclear physicist: True quantum magic only starts with multiple particles

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entanglement or quantum interference/IFJ, PAN

From the Henryk Niewodniczanski Institute of Nuclear Physics of the Polish Academy of Sciences

The world of quantum phenomena is full of paradoxes incomprehensible to human intuition and inexplicable to classical physics. This is the thesis we almost always hear when it comes to quantum mechanics. Here are some examples of phenomena that are commonly considered to be typically quantum: a single electron generating interference fringes behind two slits, as if it were passing through both at the same time; particles that are in different states at the same time, only to appear “magically” in one selected state at the moment of observation; measurements without interactions; erasing the past by means of a quantum eraser; or finally, nonlocality, which gives the impression that entangled particles are immediately interacting over any long distance. But do all these phenomena necessarily have to be purely quantum?

In an article that has just been published, Dr. Pawel Blasiak from the Institute of Nuclear Physics of the Polish Academy of Sciences (IFJ PAN) in Cracow showed how to construct, from the building blocks of classical physics, broadly understood optical interferometric systems, faithfully reproducing the strangest predictions of quantum for single particles. The presented model helps us to understand better why quantum mechanics is needed and what it really tells us about our surrounding reality that is new. If a quantum effect has a simple classical explanation, one should not go looking for any particular secret in it. The publication clearly indicates the boundary beyond which quantum theory becomes essential: true quantum “magic” only starts with multiple particles.

So, Feynman or Schrödinger? Schrödinger seems to have got to the very heart of quantum mechanics. But the silent winner could be… Albert Einstein, who was never satisfied with the commonly accepted interpretation of quantum mechanics. Without his stubborn questions we would have neither Bell’s theorem nor the field of quantum information today.”Where is it, the foundation of quantum reality?” at Eurekalert

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See also: The cat is back: Is quantum theory, dead, alive, or contradicting itself

I'l be d#$mned. I agree with ba. jdk
I don't expect this new classical loophole to survive long. It reminds me of this other recent classical loophole that was quickly closed:
Closed Loophole Confirms the Unreality of the Quantum World - July 25, 2018 After researchers found a loophole in a famous experiment designed to prove that quantum objects don’t have intrinsic properties, three experimental groups quickly sewed the loophole shut. The episode closes the door on many “hidden variable” theories. Excerpt: Chaves’s team then proposed a twist to Wheeler’s experiment to test the loophole. With unusual alacrity, three teams raced to do the modified experiment. Their results, reported in early June, have shown that a class of classical models that advocate realism cannot make sense of the results. Quantum mechanics may be weird, but it’s still, oddly, the simplest explanation around.,,, Hidden Variables That Remain Kaiser is impressed by Chaves’s “elegant” theoretical work and the experiments that ensued. “The fact that each of the recent experiments has found clear violations of the new inequality … provides compelling evidence that ‘classical’ models of such systems really do not capture how the world works, even as quantum-mechanical predictions match the latest results beautifully,” he said.,,, Kaiser, even as he lauds the efforts so far, wants to take things further. In current experiments, the choice of whether or not to add the second phase shift or the second beam splitter in the classic delayed-choice experiment was being made by a quantum random-number generator. But what’s being tested in these experiments is quantum mechanics itself, so there’s a whiff of circularity. “It would be helpful to check whether the experimental results remain consistent, even under complementary experimental designs that relied on entirely different sources of randomness,” Kaiser said.,,, To this end, Kaiser and his colleagues have built such a source of randomness using photons coming from distant quasars, some from more than halfway across the universe. The photons were collected with a one-meter telescope at the Table Mountain Observatory in California. https://www.quantamagazine.org/closed-loophole-confirms-the-unreality-of-the-quantum-world-20180725/
In fact, this following experiment may have already falsified his "new' classical model for single particles
Quantum experiment verifies Einstein's 'spooky action at a distance' - March 24, 2015 Excerpt: An experiment,, has for the first time demonstrated Albert Einstein's original conception of "spooky action at a distance" using a single particle. ,,Professor Howard Wiseman and his experimental collaborators,, report their use of homodyne measurements to show what Einstein did not believe to be real, namely the non-local collapse of a (single) particle's wave function.,, According to quantum mechanics, a single particle can be described by a wave function that spreads over arbitrarily large distances,,, ,, by splitting a single photon between two laboratories, scientists have used homodyne detectors—which measure wave-like properties—to show the collapse of the wave function is a real effect,, This phenomenon is explained in quantum theory,, the instantaneous non-local, (beyond space and time), collapse of the wave function to wherever the particle is detected.,,, "Einstein never accepted orthodox quantum mechanics and the original basis of his contention was this single-particle argument. This is why it is important to demonstrate non-local wave function collapse with a single particle," says Professor Wiseman. "Einstein's view was that the detection of the particle only ever at one point could be much better explained by the hypothesis that the particle is only ever at one point, without invoking the instantaneous collapse of the wave function to nothing at all other points. "However, rather than simply detecting the presence or absence of the particle, we used homodyne measurements enabling one party to make different measurements and the other, using quantum tomography, to test the effect of those choices." "Through these different measurements, you see the wave function collapse in different ways, thus proving its existence and showing that Einstein was wrong." http://phys.org/news/2015-03-quantum-einstein-spooky-action-distance.html
,,, also from the article in the OP:
The article in Physical Review A demonstrated the principles of constructing models of any complex optical systems built of elements functioning according to the principles of classical physics with the addition of certain local hidden variables, to which we have only indirect access.
I seriously don't see why he thinks his 'new' hidden variable model will fair much better than other hidden variable theories have. Advances in quantum mechanics have a long history of shooting down all hidden variable models that have been postulated.
Einstein vs quantum mechanics, and why he'd be a convert today - Margaret Reid - June 13, 2014 In a nutshell, experimentalists John Clauser, Alain Aspect, Anton Zeilinger, Paul Kwiat and colleagues have performed the Bell proposal for a test of Einstein's hidden variable theories. All results so far support quantum mechanics. It seems that when two particles undergo entanglement, whatever happens to one of the particles can instantly affect the other, even if the particles are separated! http://phys.org/news/2014-06-einstein-quantum-mechanics-hed-today.html A Critique of Bohmian Mechanics (Pilot Wave theory) - (2018) video https://www.youtube.com/watch?v=pn2hoU4jaQQ The One Theory of Quantum Mechanics That Actually Kind of Makes Sense – But most physicists don’t buy it. – Dec 1, 2016 Excerpt: pilot-wave theory requires that “hidden variables” exist,,, But despite Einstein’s reservations, multiple mathematical theorems have all but proven that hidden variables cannot explain away all of the bizarre behaviors seen in quantum mechanics. The most recent and famous being John Stewart Bell’s theorem, which concludes that, “No physical theory of local hidden variables can ever reproduce all of the predictions of quantum mechanics.” http://www.popularmechanics.com/space/a24114/pilot-wave-quantum-mechanics-theory/ Quantum correlations do not imply instant causation – August 12, 2016 Excerpt: A research team led by a Heriot-Watt scientist has shown that the universe is even weirder than had previously been thought. In 2015 the universe was officially proven to be weird. After many decades of research, a series of experiments showed that distant, entangled objects can seemingly interact with each other through what Albert Einstein famously dismissed as “Spooky action at a distance”. A new experiment by an international team led by Heriot-Watt’s Dr Alessandro Fedrizzi has now found that the universe is even weirder than that: entangled objects do not cause each other to behave the way they do. http://phys.org/news/2016-08-quantum-imply-instant-causation.html Quantum physics says goodbye to reality - Apr 20, 2007 Excerpt: Many realizations of the thought experiment have indeed verified the violation of Bell's inequality. These have ruled out all hidden-variables theories based on joint assumptions of realism, meaning that reality exists when we are not observing it; and locality, meaning that separated events cannot influence one another instantaneously. But a violation of Bell's inequality does not tell specifically which assumption – realism, locality or both – is discordant with quantum mechanics. Markus Aspelmeyer, Anton Zeilinger and colleagues from the University of Vienna, however, have now shown that realism is more of a problem than locality in the quantum world. They devised an experiment that violates a different inequality proposed by physicist Anthony Leggett in 2003 that relies only on realism, and relaxes the reliance on locality. To do this, rather than taking measurements along just one plane of polarization, the Austrian team took measurements in additional, perpendicular planes to check for elliptical polarization. They found that, just as in the realizations of Bell's thought experiment, Leggett's inequality is violated – thus stressing the quantum-mechanical assertion that reality does not exist when we're not observing it. "Our study shows that 'just' giving up the concept of locality would not be enough to obtain a more complete description of quantum mechanics," Aspelmeyer told Physics Web. "You would also have to give up certain intuitive features of realism." http://physicsworld.com/cws/article/news/27640 Quantum Measurements: Common Sense Is Not Enough, Physicists Show - July 2009 Excerpt: scientists have now proven comprehensively in an experiment for the first time that the experimentally observed phenomena cannot be described by non-contextual models with hidden variables. http://www.sciencedaily.com/releases/2009/07/090722142824.htm Can quantum theory be improved? - July 23, 2012 Excerpt: However, in the new paper, the physicists have experimentally demonstrated that there cannot exist any alternative theory that increases the predictive probability of quantum theory by more than 0.165, with the only assumption being that measurement (conscious observation) parameters can be chosen independently (free choice, free will, assumption) of the other parameters of the theory.,,, ,, the experimental results provide the tightest constraints yet on alternatives to quantum theory. The findings imply that quantum theory is close to optimal in terms of its predictive power, even when the predictions are completely random. http://phys.org/news/2012-07-quantum-theory.html
Of humorous note:
“When Bohm expressed “hope” that violations of QM (Quantum Mechanics) would be found later and hidden variables supported, Bohr responded that the strange sentence is almost isomorphic to “I hope that 2×2=5 will be proven at some point which will have a good effect on our finances.”

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