Wednesday, May 31, 2023

Bell's Theorem Assumes Classicality

There is currently a debate on whether the Wikipedia article on Toggle the table of contents Bell's theorem should say that it proves nonlocality. It does not, but people keep arguing that it does. So did Bell, in his later life. The article correctly says:
Bell's theorem is a term encompassing a number of closely related results in physics, all of which determine that quantum mechanics is incompatible with local hidden-variable theories given some basic assumptions about the nature of measurement.
There are some hidden assumptions: no retrocausality, no parallel universes, and no superdeterminism.

A new paper addresses this issue:

Gomori, Marton and Hoefer, Carl (2023) Classicality and Bell's Theorem. [Preprint]

A widespread view among physicists is that Bell's theorem rests on an implicit assumption of “classicality,” in addition to locality. According to this understanding, the violation of Bell’s inequalities poses no challenge to locality, but simply reinforces the fact that quantum mechanics is not classical. The paper provides a critical analysis of this view.

It explains:
Many physicists are unimpressed by Bell’s theorem. A widespread view is that Bell’s reasoning rests upon an implicit assumption of “classicality” that directly go against the fundamental principles of quantum mechanics (QM). According to such an understanding, the violation of Bell’s inequalities poses no challenge to our causal picture of the world (locality, in particular), but simply reinforces the fact that QM is not classical. One proponent of such a view is Reinhard Werner, who concisely puts it like this (Werner 2014a, p. 4):
Bell showed (maybe against his own intentions ...) that classicality and locality together lead to false empirical conclusions. Of course, all the talk about the non-locality of quantum mechanics really says [is] that any classical extension violates locality ...
In line with this picture, physicist have developed various interpretations of quantum theory that are claimed to be local and non-classical. Among recent variants are Werner’s operational quantum mechanics (Werner 2014a,b) and Robert Griffiths’s consistent histories approach (Griffiths 2020).

Others object to this view. Criticizing Werner’s position about the EPR argument and Bell’s theorem, Tim Maudlin (2014b, pp. 1-2) writes:

Werner thinks that Bell and Einstein and I have all tacitly made an assumption of which we are unaware, an assumption he labels C for ‘classicality’. ... Werner concedes that Bell proved that any classical theory that violates his inequalities must be non-local. But deny classicality and the arguments no longer go through.
That's right. Assuming a local hidden variable theory is essentially the same as assuming classicality. QM does not make that assumption, so Bell's theorem says nothing about QM. Several QM interpretations are local. QM physicists are correct that Bell's theorem has no relevance to them.

The Nobel Prize was recently given to Bell theorem tests, but the citation pointedly avoid saying that anyone proved nonlocality.

The paper goes on to make these points.

  • Bell does indeed assume classicality. It prefers to say that he has "standard causal-statistical assumptions", and these imply classicality. So it is correct to say Bell's theorem is about classical mechanics, not QM.
  • Some people define locality in a way that assumes classicality. For those people, all non-classical theories are nonlocal by definition, and this has nothing to do with Bell's theorem. It is just a wrong definition.
  • Philosophers and physicists are at an impasse, with physicists following QM and philosophers pursuing what they would like to believe.

    It ends with:

    As philosophers, we would only ask that the physicists refrain from making two sorts of statements (i) Saying that the QM treatment of EPRB is perfectly local (though they can perfectly well say that the QM treatment is not overtly non-local!). (ii) Saying that Bell did not prove what many philosophers think he proved, because he made a tacit and inappropriate presupposition of “classicality” in his argument.
    This is funny. The whole paper explains that leading QM interpretations are local, and that Bell made a classicality assumption. The assumption is explicit in Bell's earlier papers, and concealed in his later ones, but it is always made.

    In other words, physicists tell the truth, and it embarrasses philosophers who cling to mystical beliefs in nonlocality.

  • Monday, May 29, 2023

    Woke Mob get Astro Paper Withdrawn

    The arXiv preprint server has this:
    This paper has been withdrawn by Lauren Weiss
    [Submitted on 31 Mar 2023 (v1), last revised 7 Apr 2023 (this version, v2)]
    The Kepler Giant Planet Search. I: A Decade of Kepler Planet Host Radial Velocities from W. M. Keck Observatory ...

    Comments: It has come to my attention that there are significant concerns about the author list of this manuscript. It is very important to me that I honor everyone's contribution to this work appropriately. Accordingly, I am revisiting the author list, with the goal of setting a standard for authorship that fairly acknowledges everyone's contribution. -- LMW

    AAAS Science explains:
    Within 2 weeks after a preprint was posted to arXiv on 31 March, outrage erupted on Twitter and multiple co-authors requested their names be removed. The issue wasn’t the science, which focused on the detection of exoplanets, but its authorship. To the dismay of many astronomers, Geoff Marcy was listed as the third of 16 authors.

    Marcy was once a prominent astronomer at the University of California (UC), Berkeley, known for leading efforts to search for planets in other solar systems, and he was key to the formation of a multi-investigator project called the Kepler Giant Planet Search (KGPS) that gathered the data behind the recent preprint. In 2015, BuzzFeed News published a bombshell story reporting details of a university investigation

    Okay, an online gossip site published a character assassination, but why would that stop a paper on extraterrestial planets?

    Even if Marcy was guilty of some bad behavior ten years, I do not see what that has to do with publishing an astronomy research paper.

    Lawrence M. Krauss has the full story. Weiss was a grad student of Marcy, but probably not the chief villain here.

    Wednesday, May 24, 2023

    Poincare and Einstein on Mass-Energy Equivalence

    Einstein's most famous equation is E = mc2. Supposedly it created the Atomic Age.

    New article:

    Poincare and Einstein on Mass-Energy Equivalence: A Modern Perspective on their 1900 and 1905 Papers
    Patrick Moylan

    Both Poincaré in his 1900 Festschrift paper \cite{Poincare} and Einstein in his 1905 \textsl{Annalen der Physik} article \cite{Einstein} were led to $E=mc^2$ by considering electromagnetic processes taking place in vacuo. Poincaré's treatment is based on a generalization of the law of conservation of momentum to include radiation. Einstein's analysis relies solely on energy conservation and the relativity principle together with certain assumptions, which have served as the source of criticism of the paper beginning with Max Planck in 1907. We show that these objections raised by Planck and others can be traced back to Einstein's failure to make use of momentum considerations. Relevance of our findings to a proper understanding of Ives' criticism of Einstein's paper is pointed out.

    Planck criticized Einstein's derivation in 1907. Various Einstein biographers and idolizers have attempted to support Einstein, but his 1905 work was inferior to what Poincare did in 1900.

    Einstein never believed that an atomic bomb was possible, until Szilard and others convinced him around 1940.

    Einstein never cites the Poincare 1900 paper, or the Hasenoehrl 1904 and 1905 papers on the subject. For Einstein's derivation to work, he needs radiation to have momentum, but never mentions it.

    So how did Einstein do it? The obvious possibilities are: (1) he made a blunder, and just happened to get the right answer; (2) he read the Poincare and Hasenoerhl papers, and learned about radiation momentum from them; or (3) he rediscovered radiation momentum on his own, but did not think it was important enough to mention.

    Considering that Einstein spent his whole life concealing and lying about his sources, the obvious conclusion is (2). His most famous relativity papers do not cite any sources, even though they directly build on the work of others. He spent his whole life pretending that he did not know about Poincare's work.

    There is a myth that Einstein worked in isolation and obscurity, but that is not true. He was very well read on current Physics, and often wrote reviews of current research papers. The above paper says:

    After all, it is hard to imagine that Einstein, at the time he wrote his paper, was not aware of Poincar ́e’s Festchrift article, which was one of the most important and widely read physics papers of that time [41], and it seems almost certain he would have been aware of Hasen ̈ohrl’s papers published some months before in the same journal to which he submitted his first two relativity papers [28].
    Before his death, someone finally confronted Einstein with the fact that Poincare had published all of his relativity ideas beforehand, and Einstein had no response.

    The above paper does a good job of explaining the mental gymnastics that the Einstein idolizers have done to defend him.

    Monday, May 22, 2023

    Many-worlds is not an Interpretation

    Scott Aaronson, a quantum mechanics (QM) and quantum computer (QC) expert, writes:
    There’s no such thing as a “many worlds theorem.” Many worlds is an interpretation. There’s a genuine case for it but the case is philosophical, and remains argued about by people who understand everything there is to know about the subject. ...

    No, many-worlders and non-many-worlders make exactly the same predictions for what QCs will and won’t be able to do. That’s why many worlds is an “interpretation,” rather than a competing empirical theory!

    I challenged him on this, and he replied:
    I’m aware of all of this. The hardcore many-worlders think that non-many-worlders have a nonsense theory from which one shouldn’t be able to make predictions at all, and the hardcore Copenhagenists, QBists, etc. think exactly the same of many-worlders. Nevertheless, they do make the same predictions, regardless of whether they should! đŸ™‚

    At least, they do to whatever extent they accept the empirical recipe of QM. People who deny the empirical recipe are (I’d say) neither many-worlders nor Copenhagenists nor QBists nor etc., but believers in a rival physical theory (whether or not they have clear ideas about what the rival theory is).

    And as for the QC skeptics who accept QM, but believe some yet-to-be-discovered principle “censors” or “screens off” scalable QC? I’d hope that even they could still make the same conditional predictions: “yes, if it weren’t for our yet-to-be-discovered principle, then this is how a QC would operate, and this is the class of problems it could solve in polynomial time.”

    : The I no longer agree with calling many-worlds an "interpretation". It would be if they accepted the empirical recipe of QM, but they don't.

    The empirical recipe gives unique outcomes to experiments, but the many-worlders deny that. David Deutsch is a many-worlder, and he says a QC would prove the parallel universes.

    I guess I am the skeptic who accepts QM, but believes some yet-to-be-discovered principle “censors” or “screens off” scalable QC. Scott has become a many-worlder, so he would probably also say I must believe in some yet-to-be-discovered principle that collapses the wave function.

    This is not exactly my view. I am a positivist, and do not believe in yet-to-be-discovered principles. I accept what Scott calls "the empirical recipe of QM". How could I not? It works amazingly well.

    I am skeptical about scalable QC.

    I am also skeptical about intelligent life on other planets. Not because I believe in a yet-to-be-discovered principle. It just seems unlikely to me.

    Scott's main point is to attack Kaku's new book on quantum supremacy, which I also attacked on May 6.

    Thursday, May 18, 2023

    How Einstein's Quantum Realism was First Rebutted

    I did not know that the 1935 Einstein EPR paper was rebutted before Bohr:
    It must be observed that Bohr article was not the first response to EPR appearing in print in the physical review. Arthur E. Ruark in a very short paper focused on the previous quotation of EPR and developed the strongly positivist conclusion (iii):
    This [EPR] conclusion is directly opposed to the view held by many theoreticians, that a physical property of a given system has reality only when it is actually measured, and that wave mechanics gives a faithful and complete description of all that we can learn from measurements.
    That is correct.

    The above paper makes a silly argument that Einstein and Bohr were both wrong. It says:

    Of course this was just the beginning of the story: In 1964 John Bell, based on EPR work, discovered his famous theorem ([3], chap. 2) firmly establishing that quantum mechanics (irrespectively of being complete or incomplete) must be nonlocal.
    No, this is false. Quantum mechanics is local. The 2022 Nobel Prize went to Bell theorem experiments, and the citation conspicuously avoided saying that QM is nonlocal.

    Monday, May 15, 2023

    Nazis Attacked Einstein's Jewish Science

    Philip Ball wrote a 2014 book on Nazi Physics, and a chapter was excerpted in SciAm.
    Anti-Semitism did not just deprive German physics of some of its most valuable researchers. It also threatened to prescribe what kind of physics one could and could not do. For Nazi ideology was not merely a question of who should be allowed to live and work freely in the German state—like a virus, it worked its way into the very fabric of intellectual life. Shortly after the boycott of Jewish businesses at the start of April 1933, the Nazified German Students Association declared that literature should be cleansed of the “un-German spirit”, resulting on 10 May in the ritualistic burning of tens of thousands of books marred by Jewish intellectualism. These included works by Sigmund Freud, Bertolt Brecht, Karl Marx, Stefan Zweig and Walter Benjamin: books full of corrupt, unthinkable ideas. Into some of these pyres, baying students threw the books of Albert Einstein.
    I am skeptical about this. Books by Freud and Marx are indeed full of corrupt ideas that the Germans were better off without. Germany was at risk of a Marxist revolution like Russia's.

    Einstein's books were irrelevant by the time the Nazis came to power. Relativity had been written into the textbooks by then.

    Here is how he trashes a couple of Nobel Prize winners.

    The fact is that Lenard was a rather unremarkable man: an excellent experimental scientist in his heyday, but of limited intellectual depth, and emotionally and imaginatively stunted. When circumstances contrived to carry him further than his talents should have permitted, he was forced to attribute his shortcomings to the deceptions and foolishness of others. This combination of prestige and deluded self-image is invariably poisonous. ...

    Like Lenard, Stark was an experimentalist befuddled by the mathematical complexity that had recently entered physics. He was another extreme nationalist whose right-wing views had been hardened by the First World War. He too felt that Einstein had stolen his ideas, this time over the quantum-mechanical description of light-driven chemical reactions. (Stark never in fact fully accepted quantum theory, even though an understanding of the “Stark effect” depended on it.) And being a mediocrity who struck lucky, he found himself being passed over for academic appointments to which he was convinced he had the best claim.

    Einstein never fully accepted quantum theory either, and was also befuddled by mathematical complexity.

    The stories are interesting, but in the end, the Nazis did not have much influence on Physics:

    But the truth was that, while the dispute rumbled on through the late 1930s, the Nazis tightened their grip on German science regard­less. In some disciplines, such as chemistry, scientists fell into line in short order. In a few, such as anthropology and medicine, the collu­sion of some researchers had horrific consequences. Physics was another matter: just docile enough for its lapses, evasions and occa­sional defiance to be tolerated. The physicists were errant children: grumbling, arguing among themselves, slow to obey and somewhat lazy in their compliance, but in the final analysis obliging and dutiful enough. If they lacked ideological fervour, the Nazis were pragmatic enough to turn a blind eye.
    I am not sure what the Jewish Science was. By the time the Nazis came to power, Einstein was determinist, Communist, Zionist, quantum-denier, and pursuer of bogus unified field theory. He was not doing any real science anymore.

    And yet Nazi attempts to cancel Einstein seem trivial by modern standards. The Ball SciAm article gives this example:

    In 1942 Sommerfeld was about to publish some lectures on physics when he received a letter from Heisenberg saying (as Rudolf Peierls later recalled it) that “a political adviser and close friend of mine, also a physicist, would like to call to your attention certain guidelines which are now in use, that is, we note, the publisher noticed that you mentioned Einstein’s name four times in your lectures, and we wondered if you couldn’t get by with mentioning him a little less often?” Sommerfeld complied, retaining just one of the references. “I must mention him once”, his conscience obliged him to write back. Peierls adds that “after the war the names were quickly put back in”.
    So the number of Einstein citations was changed from 4 to 1, and back to 4. Nowadays, scientists are canceled for ideological reasons all the time, and Einstein is cited about 1000 times more than he deserves.

    Monday, May 8, 2023

    Droste Discovered the Schwarzschild Metric

    The Schwarzschild metric is famous for describing a black hole in general relativity. It was discovered in 1915 immediately after publication of the field equations by Einstein and Hilbert, although the significance of black holes was only figured out much later.

    I recently learned that this metric was independently discovered by a student of Lorentz.

    From a 2002 paper:

    Johannes Droste’s “Field of a single center in Einstein’s theory of gravitation, and the motion of a particle in that field.” It is a remarkable paper, arguably one of the most remarkable in the annals of general relativity and yet, although the paper is known to historians of science, practitioners of relativity themselves have been almost universally unaware of its existence for nearly a century, and no mention of it appears in any standard text. ...

    We know little about Johannes Droste. From what we do know (see the biographical note), Einstein’s theory of gravitation was the subject of his Ph.D. thesis. As he tells us in the introduction to the current paper, he had been working on the equations of motion in general relativity as early as 1913 after Einstein published a preliminary version of the field equations.

    The birth of Newtonian gravity is considered to be the central force law, although the field equations came much later. For general relativity, the birth is considered to be the field equations, not the central force law.

    I am not sure why. The Schwarzschild-Droste metric is the analog of the central force law. It is what you want for celestial orbits. Einstein and Grossmann published an "Entwurf" theory in 1913, saying Ricci = 0 in empty space. Einstein retracted this in subsequent papers, but it is apparently what Droste used to figure out the correct central force law.

    If Einstein had never met Hilbert in 1915, and they never published their field equations, we still might have had the essence of the theory from Droste's work. Probably Lorentz contributed also.

    Saturday, May 6, 2023

    Kaku Plugs Quantum Supremacy

    Here is a new interview of Michio Kaku on Quantum Supremacy:
    Theoretical physicist Michio Kaku discusses his new book, Quantum Supremacy: How the Quantum Computer Revolution Will Change Everything. He explores how quantum computing may eventually illuminate the deepest mysteries of science and solve some of humanity’s biggest problems, like global warming, world hunger, and incurable disease.
    From Peter Woit's blog:
    Out of interest, why is there no public effort by physicists to counter the relentless nonsense coming from Kaku?

    I know that there is a LOT of hype and inaccurate information in pop Sci books and science magazines, but Kaku seems to be responsible for a disproportionately large share of the garbage! ...

    That’s a good question, one I’ve asked people over the years. On the string theory front, Kaku has been writing misleading popular books on the topic for over 35 years. Most string theorists agree, at least privately, that what he writes and says has become increasingly inaccurate and increasingly embarrassing. They generally however make the argument: “dealing with this is not my responsibility, there’s loads of misleading stuff out there about science. And, maybe it will have a positive effect, getting young people and the public interested in this kind of science, going on to read better books.” ...

    As for his nonsense about quantum computing, there’s so much promotional bullshit going on that it’s understandable that anyone wanting to do something about this has no particular reason to start with Kaku.

    Woit also recommend this rambling video on string theory lied to us and now science communication is hard. Yes, I think that the credibility of all physicists is diminished by crackpot claims going unrebutted.