Art HobsonProf of Physics, Univ. of Arkansas, 1964-present (1964–present) · Author has 5.9K answers and 2.3M answer views · 3y · No. The thing that troubled Einstein the most about quantum physics was that its “spooky action at a distance” seemed to violate his special theory of relativity, not to mention common sense. Since 2015, we’ve known that Einstein was wrong about this. Spooky action at a distance (called non-locality) exists and it does not violate the special theory of relativity. The first real evidence for non-locality was a “Bell test” experiment by John Clauser in 1972, followed by Alain Aspect’s experiment in 1982. Since then, there have been many Bell-test experiments, culminating with three experiments in 2015 that closed all the plausible loopholes.

Sagnac's experiment, known as the Sagnac effect, was not conducted with the intention of disproving Einstein's theory of relativity. Instead, it was designed to test the properties of light in rotating systems. Georges Sagnac, a French physicist, performed the experiment in 1913 to demonstrate the existence of the aether, which was a hypothetical medium thought to fill the universe and through which light waves were believed to propagate.

The Sagnac effect is significant for the GPS: the Sagnac time correction in the Global Positioning System:

Lalli says that historically there was little knowledge of the Sagnac effect and little debate about its interpretation.

Sagnac performed an experiment with an interferometer, which he interpreted as a verification of the existence of the ether:

A fun read.

The two particles are therefore entangled (entanglement means inseparability) but this entanglement gradually weakens

Impressed by the EPR paper, Schrödinger responded with a series of publications in 1935, "The Present Situation in Quantum Mechanics". Schrödinger invented the cat paradox:

Shortly after publication of the EPR paper, Erwin Schrödinger wrote to Einstein to congratulate him and he added: "The separation process is not at all encompassed by the orthodox scheme" of quantum mechanics to which Einstein replied (quoted in The Shaky Game):Dear Schrödinger, I was very happy with your long letter, which dealt with my little paper. For reasons of language, this one was written by Podolsky after many discussions. But still it has not come out as well as I really wanted; on the contrary, the main point was, so to speak, buried by the erudition… A Talmudic philosopher [probably Niels Bohr] is anti-realist.

to demonstrate that the Heisenberg uncertainty principle fails because quantum mechanics is incomplete:

Gali WeinsteinPhD. Foundations (history, philosophy) of physics. · 5y · Was Albert Einstein troubled by Quantum Physics only because it conflicted with his General Theory of relativity?Einstein the realist did not object to quantum mechanics. His primary difficulty was with a probabilistic interpretation of quantum mechanics and the inseparability (entanglement) in quantum mechanics. He, therefore, strived to derive the main results of quantum mechanics from a deterministic unified field theory (a unification of a refined form of general relativity and electrodynamics) in which there would be no inseparability problem. Of course, particles are not entangled in general relativity and it is a deterministic theory. But Einstein objected to entanglement and to a probabilistic interpretation to quantum mechanics because of his realist position and not because it conflicted with his general theory of relativity. It is our modern point of view (since Stephen Hawking’s studies in the 1970s) that quantum mechanics conflicts with classical general relativity and we thus have to find ways to reconcile the two theories. For instance, we try to do so in the form of quantum gravity. However, this is a modern point of view. It was not Einstein’s view! These are the two primary things Einstein objected to (presented in his own colourful words) in quantum mechanics:“God does not play dice”: Max Born’s probabilistic interpretation of quantum mechanics.“Spooky action at a distance”: inseparability and entanglement.First, “God does not play dice”: Max Born’s probabilistic interpretation of quantum mechanics. Ironically, it was Einstein’s own contributions to quantum physics that had prompted Born to propound his probabilistic interpretation, as Born himself attested in his 1926 paper:I hereby start from a comment of Einstein’s regarding the relation between the wave field and light quanta. He says approximately that the waves are only seen as showing the way for the corpuscular light quanta, and he spoke in the same sense of a “ghost field”. This determines the probability that one light quantum, which is the carrier of energy and momentum, chooses a definite path. The field itself, however, does not have energy or momentum. … it is obvious to regard the de Broglie-Schrödinger waves as a “ghost field”, or even better as a guiding field.Einstein’s “ghost field” was defined as “the waves are only seen as showing the way for the corpuscular light quanta”, that is, a quantum particle has a ghost field (a wave) associated with it or, the particle is guided by a field. Born wrote to Einstein a month before the above paper was published:About me, it can be told that physics-wise I am entirely satisfied since my idea to look upon Schrödinger's wave field as a “ghost field” in your sense proves better all the time.What an irony of fate that Einstein gave Born the idea to look upon Schrödinger's wave function as God playing a dice… Schrödinger introduced the wave function into quantum mechanics and tried to interpret it in terms of a wavelike model. Born wanted to find a way for reconciling particles and waves, and he was relating probability to no other thing but to Einstein’s ghost field! Alas, according to Born the wave function had no physical reality and Einstein’s ghost field became a probability amplitude. Einstein, however, objected to Born’s probabilistic interpretation of Schrödinger's wave mechanics. He also opposed to the transformation of his “ghost field” into probability amplitude! Einstein went back to the blackboard and wrote that light quanta are guided by a wave, a “gohst field” and he wrote to Born a letter on December 4, 1926, in which he expressed his strict objection to Born’s interpretation:Quantum mechanics is certainly imposing. But an inner voice tells me that it is not yet the real thing. The theory says a lot, but does not really bring us any closer to the secret of the ‘old one’. I, at any rate, am convinced that He is not playing dice.Einstein tells Born that “He is not playing dice”. Subsequently, Einstein also objected to Heisenberg uncertainty principle. The more you know about something's momentum, the less you know about its position; and the more you know about its position, the less you know about its momentum. This is the Heisenberg uncertainty principle, which Einstein could not accept. Gali Weinstein's answer to What does the quote “God doesn’t play dice with the universe” by Albert Einstein mean? Second, “Spooky action at a distance”: inseparability and entanglement. The Heisenberg uncertainty principle prompted Einstein, his assistant Nathan Rosen and Einstein’s Russian Colleague Boris Podolsky to propose the EPR argument. Here I give a pedestrian explanation of the EPR argument: Gali Weinstein's answer to What is the explanation for EPR paradox? Shortly after the publication of the EPR paper, Schrödinger wrote to Einstein to congratulate him and he added: "The separation process is not at all encompassed by the orthodox scheme" of quantum mechanics, to which Einstein replied (quoted in The Shaky Game):Dear Schrödinger, I was very happy with your long letter, which dealt with my little paper. For reasons of language, this one was written by Podolsky after many discussions. But still it has not come out as well as I really wanted; on the contrary, the main point was, so to speak, buried by the erudition… A Talmudic philosopher [probably Niels Bohr] is anti-realist.To get past the Talmudic philosopher Einstein invoked a supplementary principle, the separation principle. Einstein then explained to Schrödinger what he meant by the separation principle. Consider the two particles A and B that interact and then separate.After the interaction, the real state of AB consists precisely of the real state of A and the real state of B, which two states have nothing whatsoever to do with one another. The real state of B thus cannot depend upon the kind of measurement I carry out on A ('Separation Hypothesis' from above). But then for the same state of B there are two (and in general arbitrarily many) equally justified ψB, which contradicts the hypothesis of one-to-one or complete description of the real states.In 1947 Einstein wrote again a letter to Born:I cannot make a case for my attitude in physics which you would consider at all reasonable. I admit, of course, that there is a considerable amount of validity in the statistical approach which you were the first to recognize clearly as necessary given the framework of the existing formalism. I cannot seriously believe in it because the theory cannot be reconciled with the idea that physics should represent a reality in time and space, free from spooky actions at a distance. I am, however, not yet firmly convinced that it can really be achieved with a continuous [unified] field theory, although I have discovered a possible way of doing this which so far seems quite reasonable. The calculation difficulties are so great that I will be biting the dust long before I myself can be fully convinced of it. But I am quite convinced that someone will eventually come up with a theory whose objects, connected by laws, are not probabilities but considered facts, as used to be taken for granted until quite recently. I cannot, however, base this conviction on logical reasons, but can only produce my little finger as witness, that is, I offer no authority which would be able to command any kind of respect outside of my own hand.Einstein the realist tells Born that “physics should represent a reality in time and space, free from spooky actions at a distance”.

The answer is therefore that Fizeau’s water tube experiment does not disprove special relativity

Gali WeinsteinPhD. Foundations (history, philosophy) of physics.4,205 followers · 30 followingGalina Weinstein, Ph.D., I am diagnosed with high-functioning autism (twice exceptional). I am an expert in the foundations of special and general relativity, the history and philosophy of relativity, and an expert in Einstein’s legacy. I’ve published books and papers on Albert Einstein’s path to the special and general theories of relativity. I specialize in art history, especially Leonardo da Vinci, and I’m specifically interested in artistic diagnostics.

Gali WeinsteinPhD. Foundations (history, philosophy) of physics. · 1y · Here are the traits that might have prevented me from being accepeted to jobs for many years and also might have got me fired:Being a loner. I have the ability to be social but not too much. I have difficulty attending social meetings but I try to be friendly with people.Having a strong will, being rebellious, determined, and independent. I dropped out of a bona fide high school and I always drop out of bona fide schools. You need to attend bona fide schools to get jobs in the academy (I have a Ph.D). Throughout my studies at university, I had not attended boring classes. I am a rule breaker.Being autodidactic: teaching myself physics and mathematics, and being able to teach myself all sorts of things. People don't accept this.Having too much emotional empathy and being sensitive to people. I am sensitive to other people and have an extremely high sense of justice and fairness. I am intense in helping other people but they are not so intense in helping me…. But I burn bridges with people because I do not fit in and they reject “Good doctors” (i. e. Dr. Shaun Murphy). Dr. Murphy says in the “Good Doctor”: "There is a long and dusty trail littered with people who have underestimated me". Precisely.I have a sense of humor which people find hard to understand, and I am child-like.I show attention to detail and I also tend to correct mistakes I find in other people's papers.I have difficulty understanding that I have embarrassed people and they have difficulty understanding me. I am saying what I think, and am unable to hide my feelings. I am overly direct and frank. Dr. Murphy was asked: "Do you always talk like that? Just say whatever you're thinking when you're thinking it?" And he answered: "Yes. It's good to be honest". "I have autism, it's part of who I am". So, people are never going to crowd in our corner. But people tell Dr. Murphy that he is smart, brutally honest, has no regard to social convention, and has a problem being a leader; that he is facetious, he can't understand what anyone means. He can't express himself like an adult. His apparently robotic voice is not a charming affectation. Yeah, but I don’t have a robotic voice.I constantly feel I am taken advantage of because I trust people, and they insult me.I have a very good mastery of Einstein’s classical general relativity, and I am engaging in my special interest which is Einstein and relativity, and people are jealous. But this is the kind of obsessive behavior that is common for autism. And part of being obssesive is being highly imaginative and inventive. That is, I am highly creative and have a burst of ideas in my head. I am able to concentrate on my work for a long period of time without eating and drinking.I have skills that are much higher than those my job requires. I am not a professor. I have a lot of setbacks and very few successes.My academic papers are often times not conventional. I am not writing papers with a group of scholars. I am not part of a group of scholars. It’s not because I don’t want to be part of a group of scholars.I misinterpret the implied meaning of things and take at face value what people tell me, and I overreact and over-analyze situations. I don’t understand the unwritten social rules and ask embarrassing questions. I am socially naïve, and gullible, and I believe what people tell me. Consequently, I am taken advantage of and have no understanding of how to get on with important people. For many years, I was vulnerable to bullying. My name has been conspicuously absent from the list of speakers of conferences and seminars. I felt that people picked on me and I felt great indignation. I have been a recluse for many years, spending a lot of time alone in my room. I thought that I would not get any academic position because it involves social and political skills. I don't know how to grovel and don’t know whether one actually needs to grovel to bigwigs.I prefer wearing something casual over an elegant outfit.I know I am right but I don’t know how I know this. I have this intuition, six sense…. I also have a very good visual memory.I try to mask my real personality traits.

Einstein wrote in "Physics and Reality":13 Consider a mechanical system consisting oftwo partial systems A and B which interact with each other only during a limited time.ψ is the wavefunction before their interaction. One performs measurements on A anddetermines A's state. Then B's ψ function of the partial system B is determined fromthe measurement made, and from the ψ function of the total system. Thisdetermination gives a result which depends upon which of the observables of A havebeen measured (coordinates or momenta). That is, depending upon the choice ofobservables of A to be measured, according to quantum mechanics we have to assigndifferent quantum states ψB and ψB' to B. These quantum states are different from oneanother

The EPR paper was not written by Einstein. In a 1935 letter to Schrödinger Einsteinwrote, "For reasons of language this [paper] was written by Podolsky after manydiscussions. But still it has not come out as well as I really wanted; on the contrary,the main point was, so to speak, buried by the erudition".12

According to the EPR 1935 paper, it seems that Einstein favored a ψ-epistemic localinterpretation. However, Einstein's correspondence after 1935 on EPR, or in hispublications on EPR such as a 1936 paper "Physics and Reality", reveal that Einsteinruled out locality for ψ-ontic hidden variable theories. Indeed the only realisticinterpretation of quantum states that could possibly be local is ψ-epistemic, but the ψ-ontic model must be non-local.11

Hence, "if the quantum state is a physical property of the system and apparatus, it ishard to avoid the conclusion that each macroscopically different component has adirect counterpart in reality".20

PBR cite the above paragraph fromEinstein's 1935 letter to Schrödinger saying that for the same state of B there are twoequally justified ψB"

But note that the general ideathat two distinct quantum states may describe the same state of reality has a longhistory going back to Einstein. For example, in a letter to Schrödinger containing avariant of the famous EPR (Einstein-Podolsky-Rosen) argument, Einstein argues fromlocality to the conclusion that [... quoting Einstein's argument]. In this version of theargument, Einstein really is concerned with the idea that there are two distinctquantum states for the same reality, and not with the idea that there are two differentstates of reality corresponding to the same quantum state (the more commonlyunderstood notion of incompleteness)".

In a previous version of their ArXiv paper PBR speak more clearly: 23As far as we are aware, the precise formalisation of our question first appeared inHarrigan and Spekkens, where it is attributed to Hardy.

. Indeed PBR are aware of this possibility: "ThePBR theorem only holds for systems that have 'real physical state' – not necessarilycompletely described by quantum theory, but objective and independent of theobserver. This assumption only needs to hold for systems that are isolated, and notentangled with other systems. Nonetheless, this assumption, or some part of it, wouldbe denied by instrumentalist approaches to quantum theory, wherein the quantumstate is merely a calculational tool for making predictions concerning macroscopicmeasurement outcomes".25

However, the PBR theorem does not rule "Bohr" who believes in quantum physicsthat is epistemic complete (Wavefunctions are epistemic, but there is no underlyingontic hidden variable states theory24

It seems that the PBR theorem does not end the century-old debate about the ontologyof quantum states. It does not prove, with mathematical certitude, that the onticinterpretation is right and the epistemic one is wrong

"The general notion that two distinct quantum states may describe the same state ofreality, however, has a long history. For example, in a letter to Schrödinger containing avariant of the famous EPR (Einstein-Podolsky-Rosen) argument",

Hypotheses which seem plausible before doing an experiment should, properly,often be rejected in the light of the new evidence. This was our experience withClauser and Horne’s(33) hypothesis of no enhancement at a beam splitte

We wish Jean-Pierre Vigier a very happy birthday

e state our conclusions,namely that the photon is obsolete, that light is nothing but waves, and thatall wave fields fluctuate

The explanation of how detectors are able to extract signals from the verylarge zeropoint background is a very difficult problem which we have not yetmanaged to solve. The day that theoretical physicists begin seriously to confrontit is when they will begin, perhaps, to recover the respect of the rest of thescientific community. Despite our failure to resolve it,

But all modesof the field are already present before the intervention of the coherent beam andthe nonlinear crystal. The down conversion is, more accurately, a correlatedamplification of certain modes of the zeropoint field.

The current namefor what occurs in the crystal is parametric down conversion but this is yetanother example (like “inflexion”) of a bad concept - the “photon” - giving riseto a misleading name and description; it describes an incoming photon of thecoherent beam as converting into two completely new photons

A beamsplitter does not simply split an incoming wave into two parts; it mixes togethertwo incoming waves, one of them from the “vacuum”, to give the two outgoingwaves (see Figure 1)

hese were interpreted by Grangier, Roger and Aspectas evidence that the whole “photon” goes into one or other of the outgoingchannels

With such a description it is not possible to explain theanticorrelation data;

If we consider the “vacuum” to be empty, then it seemsalmost unavoidable to assume that the intensity of any incoming classical signalis equal to the sum of the intensities in the outgoing channels, and also that thedetection probability in both channels is proportional to the signal intensitiesin those channels.

The real zeropoint field plays a crucial role in explaining how purely wave phe-nomena may be misinterpreted as evidence of corpuscular behaviour. Recogni-tion of its role would be a convincing vindication of Max Planck(16), becausehe introduced the concept of the zeropoint field precisely in order to opposeEinstein’s Lichtquanten, which were the forerunners of photons.

If we wish to represent the output of a real atomic source, we must takeaccount not only of the fact that each atomic light signal occupies a finite timeinterval (typically about 5ns), but also that neither the time nor the directionof the emitted radiation can be controlled. (We are advocating a return to anunambiguously wave description of light, so any signal is emitted into a range ofdirections. Nevertheless, the spatial distribution of the signal will be influenced,for example, by the atom’s charge distribution at the time of emission; thiscannot be controlled.)

But we find it amazing that anyone(19) shouldtry to discuss such questions as locality and causality on the basis of waveswhich fill the whole of space and time! The single-mode representation of a realatomic signal is clearly inadequate

As for Fock states, represented, for example, by equation(7), we consider that the claims to have observed them are incorrect, and thatdiscussions on such exotic properties (quantum nonlocality, entanglement etc.),which such states would have, if they were to exist, are misguided

With respect to the “nonclassical” states of the light field currently widelyreported as having been observed, our response is that something approximatingthe squeezed vacuum, as described by equation (6), has been observed; this,however, according to our new classification, is a classical state, though notGlauber-classical

We now propose to extend this judgement to the light emit-ted in atomic-cascade and parametric-down-conversion processes, as well as themicrowave radiation contained in cavities.2

We believe that this step has already beentaken, but not fully acknowledged, by a substantial part of the quantum-opticscommunity. For example, three review articles (2−4) on light squeezing makeextensive use of phase-space diagrams, and one of them(3) states explicitly thatthe photon description of the light field is not helpful in the understanding ofthe phenomenon

the point of view,which has been anathematized by the Copenhagen school, that electromagneticwaves are real waves, in ordinary space and time, having both amplitude andphase

Yes, quantum mechanics is elegant, but only as long as it applies tosystems with a few degrees of freedom. Light fields have infinite degrees offreedom, and a mature treatment of them requires the considerably less elegantapparatus of quantum field theory - not only less elegant, but bristling with allsorts of problems associated with divergences and renormalizations.

We conclude that the “photon” is an obsolete concept, and that its misusehas resulted in a mistaken recognition of “nonlocal” phenomena.

5 Save this question. Show activity on this post. If we look at the Japanese word, there is no "Fujiyama" at all. I have a hunch that this was a mistake of a translator who transliterated 富士山 wrongly due to the kanji "yama" reading. Yet if it's a mistake, why was it so widely spreaded? Wikipedia refers to "Fujiyama" as a disambiguation to "Mount Fuji" and I even saw a Japanese book with the title "FUJIYAMA". Was it really someone's mistake or Japanese has some variation about this particular mountain?For example, here in Russia many people consider "Fujiyama" normal name where those who study Japanese consider it as a terrible inaccuracy of a translator. Where is the truth?

The name “Fuji-san” is a common way to refer to Mount Fuji in Japan. In Japanese, “Fuji” is written as 富士, and “san” is how the kanji character 山 (yama) is pronounced (on’yomi), which translates to “mountain.” So, “Fuji-san” essentially means “Mount Fuji.”

A prediction is validated by two things: a future event (the actualmeasurement whose result is required to confirm the prediction) and the right past choice(that makes possible the prediction).

A counterfactual is validatedby two things: a past event (the actual measurement whose result is required to confirmthe counterfactual) and the right future choice of measurement (that makes possible thetheoretical deduction)

In the EPR case a different choice of what tomeasure on one side has “an influence on the very conditions which define the possibletypes of predictions regarding the future behavior of the system” on the other side.

n EPR the choiceof what to measure on one side influences not the ability to talk counterfactually about apast measurement on the other side, but the ability to make a prediction about a futuremeasurement on the other side.

Stapp’s argument does not demonstrate nonlocality because that choice of what to mea-sure on the left alters no thing on the right — i.e. it is “not a mechanical disturbance.”What it does alter is what we can meaningfully say about events on the right — i.e. it is aninfluence on the conditions that permit us to make a meaningful counterfactual statement.

n deny-ing the existence of a “mechanical disturbance” while maintaining the existence of an “influ-ence” Bohr is in no way asserting the presence of a mysterious non-mechanical disturbance(“quantum nonlocality”)

But that choice on the left does have an influence on thecondition that defines the very meaning of counterfactual statements about what mighthave happened earlier on the right.

T]here is . . . no question of a mechanical disturbance of the systemunder investigation . . . [but] there is essentially the question of an influ-ence on the very conditions which define the possible types of predictionsregarding the future behavior of the system.This fragment of his longer article is virtually the entire point of his earlier very briefresponse,8

he puts it this way:It is true that in the measurements under consideration any direct me-chanical interaction of the system and the measuring agencies is ex-cluded, but a closer examination reveals that the procedure of measure-ments has an essential influence on the conditions on which the verydefinition of the physical quantities in question rests.

Bearing this in mind, consider Stapp’s fifth proposition, which translated out of hisformal notation into everyday language states (in atemporal terms) that(I) Whenever the choice of measurement on the left is L2, if the measure-ment on the right is R2 and gives +, then if R1 were instead performedthe result would be −.

hese areassertions about the outcomes of four different possible experiments (12, 22, 21, and 22)only one of which can actually be done. At most one of them can be valid

L1+ implies R1−

L1+ implies R2+

L1− =⇒/ R1 − . (13

The correlations in the outcomes of the four possible pairs ofmeasurements are encapsulated in the two-particle state, given (to within a normalizationconstant) by|Ψ〉 = |L1+, R1−〉 − |L2−, R2+〉 〈L2−, R2 + |L1+, R1−〉. (1)Here a state such as |L1+, R1−〉 indicates a simultaneous eigenstate of the commutingobservables L1 and R1 with eigenvalue + on the left and − on the right

independent

My interest here is inthe remarkable way Bohr’s critique of EPR is clarified by applying it to Stapp’s argument

W. Unruh identifies essentially the same weakness (in his discussion of Stapp’s“LOC2”) in “Is quantum mechanics non-local?”, quant-ph 9710032

[T]heoretical assumptions often allow one to say with certainty, on thebasis of the outcome of a certain experiment, what “would have hap-pened” if an alternative possible apparatus had been used.

Statements of this general kind are commonplace in physics: Theoryoften allows one to deduce from the outcome of certain measurements ona system what the outcome of some alternative possible measurementswould necessarily be

2 Lucien Hardy, “Quantum mechanics, local realistic theories, and Lorentz invariantrealistic theories,” Phys. Rev. Lett. 68, 2981-2984 (1992).1

Many of Stapp’s propositions contain counterfactual conditionals — statements aboutthe outcome of experiments that might have been performed but were not

Henry Stapp1 has subjected the strange quantum correlations discovered by LucienHardy2 to a cunning logical analysis

I point out thatthe reasoning leading to this conclusion relies on an essential ambiguityregarding the meaning of the expression “statement that refers only tophenomena confined to an earlier time” when such a statement containscounterfactual conditionals

5. Karl Popper, “Quantum mechanics without ‘The Observer’ ”, in Quan-tum Theory and Reality, ed. Mario Bunge, Springer-Verlag, Berlin, (1967)

. Arkady Plotnitsky, Complementarity, Duke University Press (1994),172-190.8

He used the ‘essentialambiguity’ that he identified, which concerned what he viewed as an overlyrestrictive view of the meaning of “without in any way disturbing a system”,to enlarge the meaning of “disturb”, not to curtail its meaning by arbitrarilylimiting the scope of logical reasoning

the faster-than-light influence that Bohr deduced from ananalysis of possible knowledge-based predictions is essentially the same as theone that I deduced from an analysis of the Hardy experiment. However, thesophistication of the Hardy experiment, in comparison to the simple EPR ex-periment, allows the nature of this influence to be exposed now more clearlythan before

This result, whichis what the analysis of the Hardy experiment shows, gives solid support toBohr’s position as opposed to EPR

But this means that one cannot pass from thefact that one can measure either q1 or p1, and hence determine either q2 orp2, to the conclusion that both results are simultaneously well defined

wouldmean that in that case connections between Nature’s choices of the outcomesof measuring q2 or alternatively p2 cannot be assumed not to depend uponwhether q1 or p1 is measured

Mermin gets involved in questions of definitions and meanings, as didBohr. But Bohr had to involve himself with such matters because he wasconfronted by a characterization of “physical reality” that was basically aliento what arises from his own knowledge-based approach. Hence he was forced,in effect, to redefine this key term to bring it into line with his own philosophy.

A main objective of my work was to rid the argument of these “real-ity” questions that have led into a philosophical quadmire of interminabledisputes

The central question in judging the adequacy of Bohr’s reply is whetherthe faster-than-light influence that he claims exists, within his knowledge-based framework of thinking, can be both sufficiently real to block the ap-plication of the EPR criterion of physical reality, yet sufficiently unreal toproduce no mechanical disturbance. That is the problem that troubled Bell,and probably everyone else who is troubled by Bohr’s argument

By this argument Bohr disputes the key EPR claim that performinga measurement on one of two correlated—but currently non-interacting—systems does not “disturb” the other.So the point of Bohr’s argument is to assert that within his knowledge-based and prediction-oriented Copenhagen framework there IS an action-at-a-distance influence, and the existence of this action-at-a-distance influenceblocks the EPR (implicit) claim that there is none, thereby blocking appli-cation of the EPR criterion of reality

hus, from Bohr’s perspective, in which the meaningof “physical reality” is tied to our acquiring the knowledge needed to makepredictions about it, measuring q1 does disturb the other system because itproduces “an influence on the very conditions which define the possible typesof predictions regarding future behavior of the [other] system.” Thus if wemeasure q1 then we cannot make a prediction about p2

Applied to the particular example that EPR considered,this consideration was shown to entail that if one sets up the system so thatq1 + q2 and p1 − p2 are both well defined, as EPR specify, then one can mea-sure either q1 or p1, but not both, and hence become able to predict eitherq2 or p2 but not both.

predictions about theoutcomes of our later possible observations, then performing one of the earlierpossible measurements may exclude the possibility of performing an alterna-tive possible one

Plotnit-sky suggests that the reason that Bell does not understand Bohr’s argumentis perhaps that he refuses to read the full argument that gives meaning tothese important phrases. I am confident that Bell, a thorough scientist, didexamine Bohr’s full argument carefully before publically criticizing it

contains an ambiguity

The meaning of Bohr’s argument has been much debated. Mermin citesPlotnitsky’s book7 for a “thoughtful critique of Bell’s statements about Bohr’sviews”. Plotnitsky roundly condemns Bell as completely failing to under-stand Bohr. Bell himself admits to not understanding Bohr’s argument, butwith the implication that Bohr’s argument does not make sense

to those have difficulty understanding Bohr’s reply

This situation, in which there is a subtle action-at-a-distance influence,but no simple direct one, certainly brings to mind Bohr’s basic claim in hisreply to EPR:[T]here is... no question of a mechanical disturbance of the system underinvestigation...[but] there is essentially the question of an influence on thevery conditions which define the possible types of predictions regarding thefuture behavior of the system.In both cases there is a denial of any (proof of a) direct mechanical distur-bance of events in the single actually occurring situation, but an affirmationof the existence of an influence of some kind.

However, the term“influence events” contains an essential ambiguity.

The meaning and validity of Bohr’s reply has been muchdebated. Karl Popper5 claims that Einstein, not Bohr, won that famousbattle. John Bell6 likewise has questioned the rationality of Bohr’s argument.

he same as the nonlocal influ-ence deduced by Bohr, and used by him to block the application ofthe criterion of physical reality proposed by Einstein, Podolsky, andRosen

he nonlocal influence deduced from theanalysis of the Hardy experiment

I agree that “the Hardy-based analysis fortifies Bohr’sposition” [p. 7, Abstract], but only because it makes one take seriously the urgent need tofind a flaw in the apparently cogent reasoning of EPR

Whether Bohr knew in his bones that there were no elements of reality

10. Lucien Hardy and John Bell before him fatally undermine the position of EPR.

what I (but not Stapp) believe to be the nature of Bohr’sreply to EPR

As I read Bohr, he too was broadly interestedin questions of definition and meaning

the influence that Bohr does identify: an influence onthe possibility of making valid predictions

Nowhere, however, do the terms“nonlocal” or “faster-than-light” or “action-at-a-distance” appear in Bohr’s reply to EPR

Iwas strongly reminded of the importance of utmost caution in all questions of terminologyand dialectics.3

for the de Broglie–Bohm theory, the particle's spin is not an intrinsic property of the particle; instead spin is, so to speak, in the wavefunction of the particle in relation to the particular device being used to measure the spin. This is an illustration of what is sometimes referred to as contextuality and is related to naive realism about operators.[54] Interpretationally, measurement results are a deterministic property of the system and its environment, which includes information about the experimental setup including the context of co-measured observables; in no sense does the system itself possess the property being measured, as would have been the case in classical physics.

Since its original proposal, the view has evolved and attracted new followers in the physics community, but has been less warmly received by philosophers. Many, it seems, share the view of Hagar (2003) that “Fuchs’ ‘thin’ realism, and the entire ‘fog from the north’ which inspires it, are nothing but instrumentalism in disguise” (p.772).Footnote 1

Below is a philosophical reflection (not only for the Zotero team).We are still able to perform J.S. Bach music because music notation and instruments have not changed whithin 3 centuries. In computer science, every 6 months, software are upgraded, functionnalities and encoding very often change too. How can we work in such conditions? How can our human society survive in such a moving context ?

Put this in your address barchrome://flags/Then go to or copy paste in searchInsecure origins treated as secureThen enabled..

Dellu November 2, 2023 edited November 2, 2023 Zotero-file can be downloaded from this fork: https://github.com/DesBw/zotero-file

Dellu November 2, 2023 This fork has up to version 0.2.1: https://github.com/lychichem/zotero-file/tags

tim820 October 30, 2023 @knutatle you just use the standard Zotero routine: Tools\Manage Attachments\Convert Linked Files to Stored Files.

An integrated PDF reader, by contrast, was by far the most frequent reason people gave for not using Zotero, and there's been an overwhelmingly positive response to the new features in Zotero 6. If it's not for you, it's not for you, but your experience of using Zotero is not universal.

I don't need a fancy pdf reader like that in Mendeley, so the deep coupling of the new note editor under the hook cannot be justified by the introducing of that reader.

You could use the excuse that not many feedbacks about table were provided. But you cannot eliminate the possibility that most heavy users may have no interest in your years-long beta development at all, like me.

ou can use Markdown syntax

very few beta testers mentioned tables during that time. We'll consider supporting them in the new editor if there's enough demand.

I tried to reinstall Zotero 5, but the database was changed and locked for Zotero 6.

For me, it is a catastroph !

I'm surprised if it doesn't use HTML at all, since the annotation templates (which control exporting PDF annotations into notes, right?) take HTML. I wonder if it might be possible to simply allow the user to reactivate TinyMCE via preferences, since the two editors are probably interchangeable in the code?

which could be changed easily in HTML mode

The new editor isn't HTML, so no HTML view, sorry.

But it's not currently possible to parse Markdown on import, no

Bell must explain theproblem with von Neumann’s then widely accepted result. He does this rather informally,condensing von Neumann’s four assumptions into “Any real linear combination of anytwo Hermitian operators represents an observable, and the same linear combination ofexpectation values is the expectation value of the combination.

Von Neumann’s proof is quite straightforward. Three decades later Andrew Gleasonproved what is now known as Gleason’s Theorem: that the density matrix form (4) followsfrom premises essentially equivalent to Assumptions A′, I, and II. Gleason does not useassumption B′ for physical quantities that are not jointly measurable. His argument isnotoriously intricate (and requires that the Hilbert space have three or more dimensions).

the resultingsubensembles would be free of dispersion:Expφ,λ(R2) = (Expφ,λ(R))2 (5)for all physical quantities R

Von Neumann addresses the question of hidden variables on p. 323.15 He asks whetherthe dispersion of any ensemble characterized by a wave function φ could result from thefact that such pure states are not the fundamental states, but only statistical mixtures ofseveral more basic states. To specify such “actual states” one would need additional data— “hidden parameters”, which we denote here collectively by λ

The Exp function characterizing a pure quantum state φ is indeed of the form (4)with the density matrix U given by |φ〉〈φ|

n modern language there must be a density matrixU , such that the Exp function for the ensemble is the trace of the product of that densitymatrix with the Hermitian operator that corresponds to that physical quantity.14

Indeed, von Neumann immediately remarks that B′ characterizes such a linear combination“only in an implicit way”, since there is “no way to construct from the measurement[instructions] for R, S, . . . such [instructions] for R + S + · · · .”8

Extending the scope of AssumptionB′ to quantities R, S, . . . that are not jointly measurable is problematic,

it is one of the most important features of quantum mechanics that not allphysical quantities can be simultaneously measured.7

f several different physical quantities R, S, . . . can be simultaneously measured

Assumption B′: (p. 311) If R, S, . . . are arbitrary physical quantities, not necessarilysimultaneously measurable, and a, b, . . . are real numbers then the expectation functionExp is linear:Exp(aR + bS + · · ·) = a Exp(R) + b Exp(S) + · · · . (1)

we are reading von Neumann just as she does.

The relation is, however, not self-evidentfor quantum mechanical quantities between which uncertainty relations hold, and in factfor the reason that the sum of two such quantities is not immediately defined at all: sincea sharp measurement of one of them excludes that of the other, so that the two quan-tities cannot simultaneously assume sharp values, the usual definition of the sum of twoquantities is not applicable.

This crucial assumption is equivalent to von Neumann’s B′.

Von Neumann assumes thatExp(R + S) = Exp(R) + Exp(S). (6)In words: the expectation value of a sum of physical quantities is equal to the sum of theexpectation values of the two quantities [her italics]: von Neumann’s proof stands or fallswith this assumption. [our italics]”

8 We conjecture that she may have found von Neumann’s blatant oversight so surprisingthat she tried, unsuccessfully, to guess what else he may have had in mind

7 Perhaps in 1935 the distinctions von Neumann relied on had not yet been absorbedinto a terminology that obscured important distinctions.10

In 1935, three years after the publication of von Neumann’s book and three decadesbefore John Bell’s criticism of that book, Grete Hermann wrote about it.26

thank Ulrich Mohrhoff for bringing Dieks, 2017, to our attention

Hermann calls von Neumann“Neumann”

when Bell mentionsthat “a measurement of a sum of noncommuting observables cannot be made by combiningtrivially the results of separate observations on the two terms” because “it requires a quitedistinct experiment,”

24 Bell often fails to distinguish between “noncommuting operators” and “not jointlymeasurable physical quantities”

3 Bell does make the distinction in an earlier introductory section, but unlike von Neu-mann he does not repeatedly insist on it. His use of “observable” to mean “physicalquantity” is unfortunate, since by 1966 most physicists used the term for both physicalquantities and Hermitian operators

emphasizes von Neumann’s distinction be-tween physical quantities and Hermitian operators.23

Bub and Dieks both take this to mean that von Neumann uses assumption B′ todefine linear combinations of physical quantities that are not simultaneously measurable.This is the entire basis for their criticisms of Bell and Hermann. If B′ is just a definition,it cannot also be an invalid assumption, as Hermann and Bell maintain. But as we shallsee below, the full set of von Neumann’s four assumptions contains another way to definelinear combinations of physical quantities that are not simultaneously measurable. Withthat alternative definition, Assumption B′ can indeed impose a nontrivial constraint onthe values an Exp function can have for such linear combinations. There is no reason toinsist that Assumption B′ must be taken as a definition

Recently posted at https://arxiv.org/abs/1802.10119; threeminor errata have been repaired, some footnotes of commentary have been added, and thepresent manuscript is announced as forthcoming

e, however, agree with Hermann’s and Bell’s reading ofvon Neumann, and believe that Bub and Dieks fail to make sense of the surprising gap invon Neumann’s argument that Hermann and Bell correctly identified.

recently Dennis Dieks, 2017, expanded on Bub, adding similar criticismof the earlier work of Hermann

Recently Jeffrey Bub, 2010, claimed that Bell had misunderstood von Neumann’s ar-gument

Unknown to Bell, Grete Hermann, 1935, had published the same criticism three decadesearlier.

ohn Bell, 1966

Bub, 2011, adds Mermin, 1993, to his list of those who read von Neumann wrong

We disagree with recent papers claiming that Hermann andBell failed to understand what von Neumann was actually doing

I thank Michael Cifone for insightful discussions on Bohm’s theory

His dynamical theory plays a similar role, in showing howEuclidean geometry can be preserved, as Bohm’s dynamical theory of measurement inexplaining how the quantum statistics can be generated in a classical or Boolean theoryof probability

Lorentzaimed to maintain Euclidean geometry and Newtonian kinematics and explain theanomalous behavior of light in terms of a dynamical theory about how rods contract asthey move through the ether

thequantum statistics defined by the trace rule for quantum observables is an artefact ofa dynamical process that is not in fact a measurement of any physical quantity of thesystem

Bohm comments [3, pp. 386–387]:This means that the measurement of an ‘observable’ is not really ameasurement of any physical property belonging to the observed systemalone. Instead, the value of an ‘observable’ measures only an incom-pletely predictable and controllable potentiality belonging just as muchto the measuring apparatus as to the observed system itself. . . . We con-clude then that this measurement of the momentum ‘observable’ leads tothe same result as is predicted in the usual interpretation. However, theactual particle momentum existing before the measurement took place isquite different from the numerical value obtained for the momentum ‘ob-servable,’ which, in the usual interpretation, is called the ’momentum.’

variables—particle positions—has reached equilibrium

For example, the momentum of a Bohmian particle is the rate of change of posi-tion, but the expectation value of momentum in a quantum ensemble is not derived byaveraging over the particle momenta. Rather, the expectation value is derived via atheory of measurement, which yields the trace formula involving the momentum op-erator if we assume, as a contingent fact, that the probability distribution of hidden6

This is pre-cisely what Bohm does in his hidden variable theory [3], on the basis of a disturbancetheory of measurement that generates the quantum statistics

In [1, p. 448], Bell constructed a toy hidden variable theory for spin-1/2 systems,i.e., for quantum systems represented on a 2-dimensional Hilbert space, in which eigen-values are assigned to the spins in all directions, given a quantum pure state |ψ〉 and avalue of the hidden variable. On the face of it, this would seem to be a counterexampleto von Neumann’s theorem

As we saw, von Neumann regarded a sum of physical quantities thatcannot be measured simultaneously as implicitly defined by the statistics, and he drewthe conclusion that such an implicitly defined physical quantity cannot be representedby the operator sum in a hidden variable theory

According to Bell, von Neumann proved only the impossibility of hidden determin-istic states that assign values to a sum of physical quantities, R+S, that are the sums ofthe values assigned to the quantities R and S, even when R and S cannot be measuredsimultaneously

sum of noncommuting operators is equal to the sum of the eigenvalues of the summedoperators. For a spin-1/2 particle, for example, the eigenvalues of σx and σy are both±1, while the eigenvalues of σx + σy are ±√2, so the relation cannot hold

As Bell pointed outin [1], for dispersion free states the expectation value of a physical quantity is equal tothe eigenvalue in the dispersion free state, and it is clearly false that the eigenvalue of a

As is well-known, Gleason’s theorem [4] later established the same result on thebasis of weaker assumptions for Hilbert spaces of more than two dimensions: in effect,II is required to hold only for simultaneously measurable quantities.

It is assumed that each physical quantity of a quantum me-chanical system is represented by a (hypermaximal)3 Hermitian operator in a Hilbertspace

he observes that we measure the energy by the measuring the frequency of thespectral lines in the radiation emitted by the electron, not by measuring the electron’sposition and momentum, computing the values of P2/2m and V (Q), and adding theresult

the question is whether the quantumprobabilities, for physical quantities construed as beables, can be derived by averagingover the distribution of dispersion free states associated with a given quantum state

in the context of the hidden variable ques-tion, he has in mind something like Bell’s notion of ‘beable,’ rather than ‘observable,’the standard terminology of quantum mechanics

Von Neumann alternates between the term ‘measurable quantity’ and ‘physicalquantity.’

2Bell [2, p.174]: “The beables of the theory are those elements which might correspond to elements ofreality, to things which exist. Their existence does not depend on ‘observation.’ Indeed observation andobservers must be made out of beables.

the notion of a physical system as characterized by a set of ‘measurablequantities’ and their functional relations

What von Neumann provedwas the impossibility of recovering the quantum probabilities from a hidden variabletheory of dispersion free (deterministic) states in which the quantum observables arerepresented as the ‘beables’ of the theory, to use Bell’s suggestive term.2

Bell rejected von Neumann’sargument as fatally flawed. In an interview for the magazine Omni (May, 1988, p. 88),he went so far as to state:1Yet the von Neumann proof, if you actually come to grips with it, fallsapart in your hands! There is nothing to it. It’s not just flawed, its silly!. . . When you translate [his assumptions] into terms of physical disposi-tion, they’re nonsense. You may quote me on that: The proof of von Neu-mann is not merely false but foolish!

Thatis, the quantum probabilities could not reflect the distribution of pre-measurementvalues of beables, but would have to be derived in some other way, e.g., as inBohm’s theory, where the probabilities are an artefact of a dynamical process thatis not in fact a measurement of any beable of the system

What von Neumannproved was the impossibility of recovering the quantum probabilities from a hid-den variable theory of dispersion free (deterministic) states in which the quantumobservables are represented as the ‘beables’ of the theory, to use Bell’s term

ll raised the question whether it could be shown that anyhidden variable theory would have to be nonlocal, and in this sense ‘like Bohm’stheory.’ His seminal result provides a positive answer to the question

Joel came up with the idea for the song when he turned 40. A chance meeting with Sean Lennon, son of John Lennon and Yoko Ono, made him realize how each subsequent generation feels things are getting worse and worse while ignoring the troubles of the past.

death metal, populated by artists such as Ozzy Osbourne and Judas Priest

The Process of creativityIn chapter 17 of Gell-Mann’s The Quark and the Jaguar, the physicist Gell-Mann explains theprocess of creativity:Stages leading to creative idea (stages expressed by Hermann von Helmholtz)- Saturation: filling our minds with everything about the problem- Incubation: letting it churn subconsciously- Illumination: idea comes at some random time or circumstanceIncubation can be aided by brainstorming, and applying random thoughts or random learningto the idea.Characteristics of those who are creative and escape to deeper basins of thought: "Thosecharacteristics include a dedication to the task, an awareness of being trapped in an unsuitablebasin, a degree of comfort with teetering on the edge between basins, and a capacity forformulating as well as solving problems."From M. Gell-Mann. The Quark and the Jaguar. Little, Brown and Co., 1994.

Imagine if, instead of atoms, there were two distant boxes, each with a ball in it. The ball might be removed and sent to you from either box. At some median location, you receive a ball in the post. Immediately, the boxes become correlated — one is empty, and the other is not — because you don’t know which box the ball came from

Upon his arrival in New York, him and Elsa were met at quarentine by Edgar Bamberger and Herbert Maass (trustees of the IAS) who handed Einstein a letter from Flexner which read, in part:“There is no doubt whatsoever that there are organized bands of irresponsible Nazis in this country. I have conferred with the local authorities […] and the national government in Washington, and they have all given me the advice […] that your safety in America depends upon silence and refraining from attendance at public functions […] You and your wife will be thoroughly welcome at Princeton, but in the long run your safety will depend on your discretion”

Figure 1. The three types of bistable images. On the left is The vase-face illusion (in figure-ground reversals). In the center is being shown the Necker cube (in perspective reversal). On the right is My girlfriend or my mother-in-law (in meaning-content

El neurocientífico y fisiólogo británico David Marr afirmaba que "la percepción es la construcción de una descripción" y este dibujo serviría para probar su teoría.

Salvador Dalí estaba fascinado por las imágenes engañosas y llegó a crear una propia con su “extraña mujer”

La obra en cuestión fue asignada en su momento al caricaturista inglés W. E. Hill, quien la publicó en 1915. Pero el hombre en cuestión no habría más que adaptado a la ilustración de un concepto original que ya circulaba alrededor del mundo en formato de tarjetas coleccionables e intercambiables.Su registro más antiguo tomó la forma de una postal de origen alemán, fechada en 1888. Un ejemplar de 1890 la tituló "Mi esposa y mi suegra", haciendo clara alusión a la diferencia generacional y de aspecto entre ambas mujeres.La misma fue luego adaptada y alterada por otros, entre los que se destacaron los psicólogos R. W. Leeper y E. G. Boring que la popularizaron entre sus pares hacia la década del treinta.

La obra fue asignada en su momento al caricaturista inglés W. E. Hill, quien la publicó en 1915

In 1930, Walther Bothe and Herbert Becker performed an experiment, which was further improved by Irène and Frédéric Joliot-Curie. These authors, however, misinterpreted their results and believed to have observed γ-rays while they had seen neutrons. After additional experimental verifications, James Chadwick gave the correct interpretation of these experiments in 1932. Immediately, the new particle, the neutron, became an essential actor of nuclear and elementary particle physics, and completely changed the whole research landscape.

A quantum algorithm succeeds not because the superposition principle allows 'the computation of all values of a function at once' via 'quantum parallelism,' but rather because the structure of a quantum state space allows new sorts of correlations associated with entanglement, with new possibilities for information-processing transformations between correlations, that are not possible in a classical state space

Article PDF first page preview

A revised version of arXiv: 1711.01604, following referees' comments

the statement (attributed to Bohr by Aage Petersen) that "there is no quantum world,"

Today I found that Microsoft PDF Printer behaviour changed

Who cares if Microsoft fixes this

Disappointed, but not surprised...