Wednesday, July 31, 2013

Bell does not imply non-locality

A new philosophy paper starts:
Bell's argument (1964; 1971; 1975) establishes a mathematical no-go theorem for theories of the micro-world. In its standard form, it derives that theories which are local (and full certain auxiliary assumptions) cannot have correlations of arbitrary strength between events which are space-like separated. An upper bound for the correlations is given by the famous Bell inequalities. Since certain experiments with entangled quantum objects have results which violate these inequalities (EPR/B correlations), it concludes that the quantum realm cannot be described by a local theory. Any correct theory of the quantum realm must involve some kind of non-locality, a `quantum non-locality'. In some sense, entangled quantum objects fundamentally depend on another, even when they are space-like separated.

While this general result is widely accepted, there is a large debate about what kind of non-locality exactly follows from the violation of Bell inequalities.
Widely accepted? No, the correct conclusion is that quantum mechanics does not allow a local hidden variable theory. Just read Bell's theorem on Wikipedia or any textbook. Of course the conventional wisdom since 1930 has been that no hidden variable theory of any kind is possible.

People who should know better say crazy things on this subject.
Cornell solid-state physicist David Mermin has described the various appraisals of the importance of Bell's theorem within the physics community as ranging from "indifference" to "wild extravagance". Lawrence Berkeley particle physicist Henry Stapp declared: “Bell’s theorem is the most profound discovery of science.”.
If you think that Bell proved nonlocality, then you would consider it very profound. But if you realize that Bell only rejected some theories that everyone rejected anyway, then it is no big deal. That is why there has never been a Nobel Prize for work related to Bell's theorem.

Monday, July 29, 2013

Equivalence between Lorentz and Einstein

Albert Einstein is considered the greatest physicist of the 20th century, with his greatest paper being his 1905 special relativity paper. To justify this fame, much has been written to try to distinguish the work from previous relativity papers by others.

An excellent new paper on this subject has just been posted by Pablo Acuña, titled On the Empirical Equivalence Between Special Relativity and Lorentz's Ether Theory. As with other scholars, he finds bizarre and contrived reasons for favoring Einstein and it is fascinating how he deals with the basic facts.

Lorentz's papers were published in 1892, 1895, 1899, and 1904. These papers were widely read, and he got the 1902 Nobel Prize for his electron theory, as it was called at the time. Lorentz had certain conceptual gaps that were filled by Poincare.
Lorentz presented all these results — the coordinate transformations and the length - contraction hypothesis — in a more systematic and structured way in his 1895 Attempt of a Theory of Electric and Optic Phenomena in Moving Bodies. This work rapidly became a central point of discussion for the scientific community of the time. Henri Poincaré introduced observations and criticisms that were important for its further development. He complained that the explanations for the negative results of ether-drift experiments of first and second order the theory provided were two different and logically disconnected parts of the theory. In 1900 he stated that "the same explanation must be found for the two cases, and everything tends to show that this explanation would serve equally well for the terms of higher order and that the mutual destruction of these terms will be rigorous and absolute" (Poincaré 1900, p. 172)4.

A second important contribution of Poincaré on Lorentz‘s theory was to elucidate that `local time‘ was not only a mathematical tool, as Lorentz originally conceived, but that it contained a physical meaning. In a contribution for a volume celebrating the 25th anniversary of Lorentz‘s doctorate, Poincaré explained his point by means of an illustration that strikingly resembles Einstein‘s method for the synchronization of clocks.
If you consider Lorentz electron theory (aka Lorentz aether theory) as understood by Poincare, it was mathematically and observationally equivalent to Einstein's 1905 theory. That was the consensus of physicists of the day, who sometimes called it the Lorentz-Einstein theory in 1906, and the consensus of scholars today. Acuna says "the expression Lorentz-Einstein theory was common before Minkowski‘s famous conference of 1908", and "began to disappear" in 1909, as it was superseded by the spacetime geometry formulation.
After this outline of the development of Lorentz‘s theory, we can clearly see that the theory which is empirically equivalent to special relativity is not the one that Lorentz formulated in 1904. The amendments and contributions that Poincaré introduced in his 1906 work and the observations and criticisms that he leveled ca. 1900 must be considered to really obtain the predictive equivalence. In other words, the case of empirical equivalence at issue concerns Einstein‘s theory and a conceptual reconstruction that we could call the Lorentz-Poincaré theory.
Next the paper turns to non-empirical reasons for favoring Einstein.
In The Logic of Scientific Discovery, Karl Popper offered a definition of ad hoc hypotheses within the context of his falsificationist framework. A hypothesis is called ad hoc if it is unfalsifiable, that is, if the 14 hypothesis does not entail any predictions that could put it `at risk‘. He mentioned the Lorentz-Fitzgerald length-contraction as a paradigmatic example of an ad hoc hypothesis—and this judgment became very influential regarding the epistemological assessment of Lorentz‘s theory. As we saw above, the LorentzFitzgerald contraction was originally introduced with the specific goal of providing an account for the negative result of the Michelson-Morley experiment. If this were the only empirical prediction for which the hypothesis is logically relevant, then it would clearly qualify as ad hoc in Popper‘s sense. Since Popper stated as a methodological principle that the introduction of new hypotheses in a given theory is allowed only if such hypotheses increase the degree of falsifiability of the theory, then the ad-hocness of length contraction is reason enough, according to Popper, to dismiss Lorentz‘s theory and favor special relativity:
An example of an unsatisfactory auxiliary hypothesis would be the contraction hypothesis of Fitzgerald and Lorentz which had no falsifiable consequences but merely served to restore the agreement between theory and experiment—mainly the findings of Michelson and Morley. An advance was here achieved only by the theory of relativity which predicted new consequences, new physical effects, and thereby opened up new possibilities for testing, and for falsifying, the theory. (Popper 2002, pp. 62-3).
Adolf Grünbaum (1959) showed that this view was mistaken. ...

It is not difficult, though, to demonstrate that the length-contraction hypothesis is not ad hoc in Popper‘s sense. ...

Besides Popper‘s, though, there remain two senses in which the length-contraction hypothesis might be accused of ad-hocness. First, it was cooked up with the only and specific goal of solving one single experimental difficulty. This is true, but as we just saw, further development of the theory connected the hypothesis with unexpected empirical results. In this sense, the length-contraction hypothesis is on an analogous stand with Planck‘s quantum of energy hypothesis — which was introduced with the only and specific goal of providing an account for the observed spectrum of black-body radiation — and in neither of the two cases this sense of ad-hocness could be invoked to reject the corresponding hypothesis, of course. Moreover, one could ask what is wrong with ad hoc hypotheses—in the sense of cooked up hypotheses—in themselves. Even if a hypothesis is helpful in providing an explanation for one single experimental result, it does contribute to enlarge the scope and fruitfulness of the corresponding theory24.

The second remaining sense of ad-hocness that could be attributed to the length-contraction hypothesis is that it was a sort of rabbit in the hat maneuver, that is, that the contraction was postulated without a justified physical underpinning. In this case, the ad-hocness accusation boils down to an accusation of implausibility. We saw above that Lorentz did propose a plausibility argument for his length-contraction hypothesis, and the fact that the same argument had been already envisioned by Fitzgerald bestows Lorentz‘s with good credentials. Moreover, the eventual fulfillment of the main goal of the electromagnetic worldview program—namely, the reduction of all physics to electromagnetism—would have provided the generalized contraction hypothesis with firm physical foundations.
I agree with this. It is silly to argue that Einstein's approach was somehow better because it was less ad hoc.
A second non-empirical feature that could be used in order to make a choice favoring Einstein‘s theory is given by the aesthetic-mathematical virtues that characterize special relativity. Actually, these features did play a historically relevant role in the matter26. Consider, for example, the following passage included in Max von Laue‘s 1911 textbook (the first ever published) on special relativity:
Though a true experimental decision between the theory of Lorentz and the theory of relativity is indeed not to be gained, and that the former, in spite of this, has receded into the background, is chiefly due to the fact that, close as it comes to the theory of relativity, it still lacks the great simple universal principle, the possession of which lends the theory of relativity an imposing appearance. (Quoted in Schaffner 1974, p, 74)
Minkowski‘s introduction in 1908 of the four-dimensional formalism in which the theory can be expressed was a crucial factor regarding the general judgment about the mathematical simplicity of special relativity. Scott Walter (2010) has offered a historical survey of the early reception of Minkowski‘s work in connection with the acceptance of special relativity. He shows that Laue‘s specific reasons to embrace Einstein‘s theory in terms of simplicity was given—in spite of its difficult visualizibility in intuitive terms — by the mathematical elegance and simplicity that the four-dimensional formulation allowed:
Laue considered Minkowski space-time as an "almost indispensable resource" for precise mathematical operations in relativity. He expressed reservations, however, about Minkowski‘s philosophy, in that the geometrical interpretation (or "analogy") of the Lorentz transformation called upon a space of four dimensions: "[A] geometric analogy can exist only in a four-dimensional manifold. That this is inaccessible to our intuition should not frighten us; it deals only with the symbolic presentation of certain analytical relationships between four variables". One could avail oneself of the new four -dimensional formalism, Laue assured his readers, even if one was not blessed with Minkowski‘s space-time intuition, and without committing oneself to the existence of Minkowski‘s four-dimensional world‘ (Walter 2010, p. 17).27
I agree that the 1908 Minkowski space-time view is aesthetically superior, but that view owes much more to Lorentz (and Poincare) than to Einstein. I document this in my book, How Einstein Ruined Physics. Other scholars ignore this.

Poincare's 1905 paper was based on Lorentz, not Einstein, and introduced the following crucial concepts. He (1) combined space and time into a 4-dimensional spacetime, (2) gave it a non-Euclidean geometry using a metric and symmetry group, and (3) recast electromagnetic variables and equations as covariant under that geometry. These are the essential ideas in Minkowski's 1908 paper, and his previous 1907 paper cites Poincare as the source. Minkowski also cites Einstein, but got nothing significant from him. Einstein rejected these ideas until after Minkowski became popular.

Thus the chain of relativity development is Maxwell 1860-1880, to Lorentz 1892-1904, to Poincare 1905, to Minkowski 1908, to Laue textbook 1911. No one has ever been able to give a convincing argument that Einstein played an important role in either the development of special relativity or in the popular acceptance of it. Einstein's reasoning did influence a few people like Max Planck in 1906, but that reasoning was obsolete by 1908.

Acuna discusses other contrived reasons for preferring Einstein.
After this review and critical assessment of Janssen‘s arguments, we can now consider the best possible formulation of what he regards as a reason to prefer special relativity. Recall that the basic idea is that in Lorentz‘s theory the fact that all the laws of physics are Lorentz-invariant remains as an unexplained coincidence; whereas in special relativity Lorentz-invariance gets naturally explained by the specific kinematics of space-time. For the reasons mentioned above, this explanation cannot be taken either as causal or as constructive. If it is an explanation at all, it has to be an explanation of principle.
When philosophers discuss distinctions between Lorentz and Einstein theories, they usually put a modern interpretation on the theories that were not necessarily articulated in 1905. For example, Acuna discusses the applicable symmetry groups but neither Lorentz nor Einstein mentioned them. It is sometimes said that Lorentz wanted a constructive theory where the contraction is caused by electromagnetic forces, and Einstein wanted a non-causal spacetime theory.

Lorentz said:
Einstein simply postulates what we have deduced, with some difficulty and not altogether satisfactorily, from the fundamental equations of the electromagnetic field. By doing so, he may certainly take credit for making us see in the negative result of experiments like those of Michelson, Rayleigh and Brace, not a fortuitous compensation of opposing effects but the manifestation of a general and fundamental principle. Yet, I think, something may also be claimed in favour of the form in which I have presented the theory. {Lorentz 1916, but from 1906 lectures]
I read this as saying that Einstein's difference was one of presentation, not substance. Lorentz derived a theorem from Maxwell's equations, and Einstein took a shortcut by just postulating the theorem.

Einstein was not opposed to Lorentz's constructive approach, but had difficulty understanding it:
So, first to the question of whether I consider the relativistic treatment of, e.g, the mechanics of electrons as definitive. No, certainly not. It seems to me too that a physical theory can be satisfactory only when it builds up its structures from elementary foundations. The theory of relativity is not more conclusively and absolutely satisfactory than, for example, classical electrodynamics was before Boltzmann had interpreted entropy as probability. If the Michelson-Morley experiment had not put us in the worst predicament, no one would have perceived the relativity theory as a (half) salvation. Besides, I believe that we are still far from having satisfactory elementary foundations for electrical and mechanical processes. I have come to this pessimistic view mainly as a result of endless, vain efforts to interpret the second universal constant in Planck‘s radiation law in an intuitive way. I even seriously doubt that it will be possible to maintain the general validity of Maxwell‘s equations for empty space. [1908 letter to Sommerfeld]
The truth is that there was very little difference between the views of Lorentz and Einstein.

Another common argument is the allegation that Lorentz believed in the aether.
The problematic status of the ether is another feature that has been typically considered as a reason to dismiss Lorentz‘s theory and to embrace special relativity. Usually, the ether is held to be problematic chiefly because it is undetectable. Since there is no possible observation that directly indicates the reality of the ether, we should simply apply Occam‘s razor and pick the most economic theory. Adolf Grünbaum, for example, has argued along this line: ...

Two objections can be leveled against this view. First, it is awkward to state that there was no physical foundation in order to postulate a preferred inertial ether frame. ...

Second, and more importantly, the automatic rejection of unobservable entities as a normative principle is debatable. ...

These remarks are enough in order to show that the standard arguments regarding the problematic status of the ether in Lorentz‘s theory are not compelling. However, there is a different perspective from which the ether can be questioned anyway. The real problem with it relies on the fact that, after Poincaré showed that the Lorentz coordinate transformations are symmetric, the ether became not only directly unobservable, but also empirically superfluous — a hypothesis is superfluous if it is logically irrelevant for the derivation of the empirical consequences of the theory it belongs to44.
After rejecting all the other reasons, Acuna ultimately gives two reasons for favoring Einstein over Lorentz. First he notes that Lorentz himself wrote papers about how his electron theory was not compatible with emerging quantum ideas of Planck and others. Second, general relativity built on Minkowski's spacetime geometry, and not Lorentz's formulation.

I am guessing that Acuna had to give some reasons for favoring Einstein, or he would not be able to get his paper published. So he added these silly reasons. It is true that the classical electrodynamics of Maxwell and Lorentz was refined by quantum mechanics, but those equations of Maxwell and Lorentz are still taught and used every day. They are as valid as ever.

Acuna disposes of a couple of general relativity misconceptions also. Some have said that the proof of Einstein's non-ad-hoc and principled thinking is that he went on to create general relativity while being guided by general covariance and ignoring experiment. But in fact he wrote papers rejecting covariance (using a fallacious hole argument), and he was driven by Poincare's use of relativity to explain anomalies in Mercury's orbit.

The inescapable conclusion is that the physicists, historians, and philosophers who idolize Einstein are wrong. They get the facts wrong, and promote a misguided view of what science is all about. The story of Einstein and relativity is one of the most commonly retold stories in the whole history of science, and there is no excuse for contradicting the primary literature.

Acuna has co-authored another paper on Another Look at Empirical Equivalence and Underdetermination of Theory Choice. It says:
Therefore, Lorentz‘s theory is usually considered as EE [empirical equivalence] to Einstein‘s special relativity. This is correct, although some cautious is needed. ... The full equivalence of the theories is obtained only if several crucial amendments and contributions introduced by Henri Poincaré are taken on board.
Lorentz's charge density formula was not quite right, and Einstein's relativistic mass formula was not quite right, and neither had the Lorentz group which was needed to show that the theory made sense. Poincare got everything correct in 1905.
Therefore, in 1906 physics was facing an instance of our problem: there were two predictively equivalent theories and the choice between them was underdetermined by empirical data. We know that in the end Einstein‘s theory won the competition. The historical course of events that led to this victory was rather complex, though. For example, between 1906 and 1909 the scientific community often spoke about the Lorentz-Einstein theory, as the difference between the two rival theories had not been generally recognized. Clarification concerning this rivalry had to wait until Minkowski‘s groundbreaking work (1908). A couple of years later, around 1911, the expression Lorentz-Einstein theory disappeared from the vocabulary of physics, and special relativity was adopted as the main-stream theory.
The expression disappeared because the Poincare-Minkowski non-Euclidean geometry formulation quickly became the dominant theory of relativity, replacing the Lorentz-Einstein theory. No, Einstein's theory did not win. The non-Euclidean geometry version of special relativity won.

Poincare and Minkowski made no use of Einstein's work. Poincare's 1905 paper was written before Einstein's. Minkowski cites Einstein, but only for clearly presenting a couple of Lorentz's ideas.

Einstein used Lorentz's work for the Michelson-Morley consequences, Maxwell's theory, FitzGerald contraction, local time, relativistic mass, and the constant speed of light. Einstein used Poincare for the relativity principle, time synchronization, and the reality of local time.

Thus there are really two observationally equivalent theories. The Lorentz-Einstein theory based on Michelson-Morley, Maxwell's equations, the relativity principle, and the constant speed of light; and the Poincare-Minkowski theory based on the non-Euclidean geometry of spacetime. The non-Euclidean geometry was the paradigm shift, and Einstein completely missed it.

Acuna's Utrecht (Dutch) thesis has more detail. He explains the argument that Einstein did not rely on experiment:
As I mentioned at the beginning of this chapter, there was a time when an essential connection was stated between the Michelson-Morley experiment and SR. That is, the former was thought to have been a direct motivation for Einstein to develop his theory. After the work of historians like Hirosige, Holton, Stachel, Miller and others, this view has finally been shown to be wrong. Einstein?s motivation was not to solve the problem of the ether. ...

After this example of the theoretical asymmetries that do not correspond to the observed phenomena, Einstein briefly refers to “the unsuccessful attempts to discover any motion of the earth relatively to the light medium”, and states that these failed attempts “suggest that the phenomena of electrodynamics as well as of mechanics possess no properties corresponding to the idea of absolute rest”78. These two observations are the only reasons that Einstein mentions in his 1905 paper as leading him to the formulation of his relativity principle. That the only specific experiment he mentions is the one of electromagnetic induction and his generic reference to the failed attempts to detect ether-wind effects clearly point out that the Michelson-Morley experiment had no special relevance for the formulation of the theory. After all, this experiment is only one more among the unsuccessful attempts to discover any motion of the earth relatively to the light medium.
The simple explanation is that Einstein got the relativity principle from Poincare, the induction from Maxwell, and the other experiments from Lorentz. Einstein even uses Poincare's term, "relativity principle". Acuna acts as if Einstein reinvented some of it on his own, but there is no evidence of that.

To get his thesis accepted, Acuna probably had to give an explanation for crediting Einstein, in spite of all the historical evidence that others had all the big ideas first.
Before finishing this section and turning to Einstein?s theory, I will make a brief and general remark about a fascinating and important issue: did Poincare independently discover SR? [special relativity] Some authors state that he did –- Giedymin, Zahar and Whittaker75. The main arguments for this conception are Poincare's analysis of the measurement of time and the determination of distant simultaneity, his amendments on the meaning of the Lorentz transformations, and the fact that he derived some mathematical results from the transformations that clearly prefigure Minkowski's space-time –- he noticed that, so that the transformations can be understood not only as rotations around the y and z-axes, but also around the x-axis and a fourth axis it –- and he also noticed that many physical quantities can be expressed as determined by four components, and that so expressed they remain invariant under Lorentz transformations.

In spite of the many results that Poincare obtained, and in spit e of the many epistemological considerations which resemble some of the ones that Einstein also did; I think that Poincare did not discover SR. Even though he made a step towards it with his right foot, his left foot and his whole body stayed in the core of classical mechanics. His relativistic glimpses are only spots in a non-relativistic backdrop.
Acuna's main arguments are that Poincare followed Lorentz's terminology in saying that clocks measure "local time" instead of "true time", and postulated a pressure (or stress) to hold the electron charge together. Supposedly these show an incorrect ontological belief in the aether, altho no one has ever been able to explain what was incorrect.

Acuna does admit that Poincare proved that his theory did not depend on any aether frame:
Poincare explicitly showed that the correct interpretation of the transformations is symmetrical, i.e., that the relevant velocities involved are the relative ones. This feature was not originally noticed by Lorentz, he interpreted them as asymmetric –- his view of the transformations was such that the transformation to go back to the ether-rest frame delivers uncontracted lengths, for example, whereas Poincare showed that both systems S and S’ determine that the lengths of bodies in (relative) motion get contracted. Curiously, as Janssen points out, Lorentz only saw this via Einstein, not via Poincare; even though he was certainly aware of his work –- Lorentz openly accepted the introduction of the Poincare-pressure, for instance74.
When Lorentz lectured on Einstein's work, this symmetry was described as if it were the main technical breakthru. It is curious that Lorentz did not appreciate Poincare's 1905 theory until years later.

The only way Acuna can credit Einstein is to credit him for Minkowski's formulation:
In addition to the mathematical and structural simplicity of Einstein's theory, its formulation in terms of the four-dimensional language introduced by Minkowski was followed by an evaluation of SR as being a very elegant theory. For example, in his 1911 paper Relativitätsprinzip und Äther, Emil Wiechert made such claim [as quoted by Walter]:
Wiechert wrote that SR theory was “brought by Minkowski to a highly mathematically-finished form.” He continued:
It was also Minkowski who, with bold courage, drew the extreme consequences of the theory for a new spacetime intuition and contributed so very much to the theory's renown.

It was precisely Minkowski's spacetime intuition, or his identification of the extreme consequences of this intuition, that had made the theory of relativity famous in Wiechert's view.132
But as explained above, Minkowski's formulation was based on Poincare's non-Euclidean geometry, and had nothing to do with Einstein. It was Minkowski's formulation that was popular in 1911, not Einstein's.
The radically new approach to physics that Einstein‟s paper contained with respect to the notions of space and time were crucially developed and clarified by the work of Hermann Minkowski. In his famous paper of 1908 Space and Time he elucidated that Einstein‟s theory implied a revolutionary reformation of the meaning of these concepts by the introduction of a four-dimensional manifold that we now call space-time.
Here is that 1908 paper, and Minkowski's earlier 1907 paper. Nowhere does either say that Einstein's theory implies anything.

The main reason for crediting Poincare is not that Poincare published published every crucial idea ahead of Einstein. The main reason is that Poincare discovered the spacetime geometry formulation that became the essence of relativity, and Einstein did not even understand it.

Saturday, July 27, 2013

Encode the universe in 300 qubits

Nature magazine reports p on the latest quantum computing hype:
Quantum computers of the future will have the potential to give artificial intelligence a major boost, a series of studies suggests.

These computers, which encode information in 'fuzzy' quantum states that can be zero and one simultaneously, have the ability to someday solve problems, such as breaking encryption keys, that are beyond the reach of ‘classical’ computers.

Algorithms developed so far for quantum computers have typically focused on problems such as breaking encryption keys or searching a list — tasks that normally require speed but not a lot of intelligence. But in a series of papers posted online this month on the arXiv preprint server1, 2, 3, Seth Lloyd of the Massachusetts Institute of Technology in Cambridge and his collaborators have put a quantum twist on AI. ...

"We could map the whole Universe — all of the information that has existed since the Big Bang — onto 300 qubits," Lloyd says.
Yes, I am skeptical. If we could make one scalable qubit, then we could make 300 and encode all the info of the universe. It would take a lot to convince me of that.

The 300 qubit estimate is in this quantum clustering paper.

This John Kelly IBM video is also enthusiastic about commercial quantum computing. In 10 years you will know whether he is right or I am right.

Friday, July 26, 2013

Crick admitted taking Franklin's data

franklindoodle_610x279Yesterday's Google doodle:
Rosalind Elsie Franklin was a British biophysicist and X-ray crystallographer who made critical contributions to the understanding of the fine molecular structures of DNA, RNA, viruses, coal, and graphite.
Watson publicly revealed in 1968 that he and Crick stole Franklin's results without telling her or properly crediting her.

Maybe her work would have been discovered anyway. Crick admitted in a 1961 letter:
On the matter of Maurice Wilkins. I think his contribution was twofold. He indicated the careful x-ray work on DNA, and since 1953 he has done numerous extensive, accurate and painstaking studies on it. It is true that he has worked rather slowly, but then hardly anybody else has done anything. However, the data which really helped us to obtain the structure was mainly obtained by Rosalind Franklin, who died a few years ago. It should also be remembered that for a whole year Jim and I tried to get Maurice to solve the structure by our approach, without success. It was only after we learnt of Pauling's structure that we asked and obtained Maurice's permission to work on the problem. Nevertheless, for the last eight years Maurice has done all the hard work on the problem and that should be recognized.
Wilkins and Watson have a history of badmouthing Franklin. Watson even claimed that he was afraid that she would physically attack him.

Thursday, July 25, 2013

50 years of paradigm shift theory

A recent article says:
Fifty years ago, Thomas Kuhn, then a professor at the University of California, Berkeley, released a thin volume entitled The Structure of Scientific Revolutions. Kuhn challenged the traditional view of science as an accumulation of objective facts toward an ever more truthful understanding of nature. Instead, he argued, what scientists discover depends to a large extent on the sorts of questions they ask, which in turn depend in part on scientists’ philosophical commitments. Sometimes, the dominant scientific way of looking at the world becomes obviously riddled with problems; this can provoke radical and irreversible scientific revolutions that Kuhn dubbed “paradigm shifts” — introducing a term that has been much used and abused. ...

Kuhn’s thesis has been hotly debated among historians and philosophers of science since it first appeared. The book and its disparate interpretations have given rise to ongoing disagreements over the nature of science, the possibility of progress, and the availability of truth. ...

Eventually, a new exemplary solution emerges. This new solution will be “incommensurable” — another key term in Kuhn’s thesis — with the former paradigm, meaning not only that the two paradigms are mutually conflicting, but that they are asking different questions, and to some extent speaking different scientific languages. ...

Kuhn relies heavily on a “particularly famous case of paradigm change”: the sixteenth- and seventeenth-century debate over whether the sun goes around the earth or the earth around the sun. (This had been the subject of Kuhn’s previous book, The Copernican Revolution [1957].) ...

It was important for Kuhn that his conception of the history and process of science was not the same as that of scientific progress. He maintained that the process of science was similar to biological evolution — not necessarily evolution toward anything, only away from previous error. In this way, Kuhn was rather skeptical about the idea of progress at all. This was the most controversial aspect of his thesis, the one that most concerned the contemporary critics of Structure, on the basis of which they accused — or celebrated — Kuhn as a champion of relativism.
String theorist Lenny Susskind sain in an interview:
Are there any philosophers of science whom you like?

I’m one of the few physicists I know who likes Thomas Kuhn. He was partly a historian of science, partly a sociologist. He got the basic idea right of what happens when the scientific paradigm shifts. A radical change of perspective suddenly occurs. Wholly new ideas, concepts, abstractions and pictures become relevant. Relativity was a big paradigm shift. Quantum mechanics was a big paradigm shift. So we keep on inventing new realisms. They never completely replace the old ideas, but they do largely replace them with concepts that work better, that describe nature better, that are often very unfamiliar, that make people question what is meant by “reality.” Then the next thing comes along and turns that on its head. And we are always surprised that the old ways of thinking, the wiring that we have or the mathematical wiring that we may have created, simply fail us.
I ownder whether Susskind understood Kuhn's notions of progress and incommensurability. Relativity and quantum mechanics were quickly confirmed by quantitative experiments. The term paradigm shift is for theories like Copernicus heliocentism that had no quantitative advantage over previous theories. Among real scientists, only fringe theorists like string theorists like Kuhn because string theory has no quantitative advantages over previous theories, and does not make progress in any objective way.

Monday, July 22, 2013

Light is quantized when observed

Galina Weinstein has a new paper on The 1905 Relativity Paper and the "Light Quantum", with historical info on Einstein:
Before submitting his 1905 special relativity paper, Einstein had submitted a paper on what came to be called his light quantum hypothesis – the only one of his 1905 papers he considered truly revolutionary: "On a Heuristic Viewpoint Concerning the Generation and Transformation of Light", sent to the Annalen on March 17th, 1905, and received by the Annalen a day afterwards.9

Einstein wrote Conrad Habicht in May 1905 about this paper, "It deals with the radiation and energy characteristics of light and is very revolutionary".10

This paper extended the range of application of Planck's 1900 quantum hypothesis. In order to explain his law of black body radiation, which had been well-verified empirically, Planck was forced to assume that oscillators interacting with the electromagnetic field could only emit and/or absorb energy in discrete units, which he called quanta of energy. The energy of these quanta was proportional to the frequency of the oscillator: E = hf. But Planck believed, in accord with Maxwell's theory, that the energy of the electromagnetic field itself could change continuously.
This is all well-known, but but just what was Einstein saying in 1905 that was different from what Planck already said in 1900? Weinstein has some correspondence that throws some light on the matter:
In 1906 Planck's assistant, Max Laue, wrote Einstein on obtaining the preprints of the 1905 light quanta paper,

"When at the beginning of your last paper, you formulate your heuristic standpoint to the effect that radiant energy can be absorbed and emitted only in specific finite quanta, I have no objections to make; all of your applications also agree with this formulation. Now, this is not a characteristic of electromagnetic process in vacuum but rather of the emitting or absorbing matter, and hence radiation does not consist of light quanta as it says in §6 of your first paper; rather, it is only when it is exchanging energy with matter that it behaves as if it consisted of them."

Laue ended his letter to Einstein by saying: "By the way, I have never discussed your heuristic point of view with my boss. It is possible that there are differences of opinion between him and me on this question."14

But indeed the boss did agree with his assistant.
I am guessing that most people assume that Einstein was right and Planck was wrong, but that is not the case. Quantum mechanics teaches that light is quantized when observed, meaning when emitted or absorbed. Light in a vacuum has wave properties, and is definitely not a particle. So Planck's 1900 view is quite close to our modern quantum mechanical view. Einstein's 1905 heuristic was an interesting proposal, but it never led to the revolution that he hoped.
In fact, Planck was the first scientist to notice Einstein's relativity paper. Einstein's paper on relativity, received by the Annalen der Physik at the end of June 1905 was already in print by 26 September. And as early of November 1905 Planck had reported favorably on it.
Planck was a big help to Einstein's career. Planck apparently did not notice the much more important relativity paper of June 5, 1905 by Henri Poincaré.

Here is an xkcd cartoon. Quantum mechanics must be the most important and also misunderstood scientific theory in history. Even when big-shots talk about it, they babble nonsense about philosophical implications.

A current SciAm article explains that, while modern physicists talk about particles all the time, the electrons and photons are really not particles.
Physicists routinely describe the universe as being made of tiny subatomic particles that push and pull on one another by means of force fields. They call their subject “particle physics” and their instruments “particle accelerators.” They hew to a Lego-like model of the world. But this view sweeps a little-known fact under the rug: the particle interpretation of quantum physics, as well as the field interpretation, stretches our conventional notions of “particle” and “field” to such an extent that ever more people think the world might be made of something else entirely.

The problem is not that physicists lack a valid theory of the subatomic realm. They do have one: it is called quantum field theory. Theorists developed it between the late 1920s and early 1950s by merging the earlier theory of quantum mechanics with Einstein's special theory of relativity. Quantum field theory provides the conceptual underpinnings of the Standard Model of particle physics, which describes the fundamental building blocks of matter and their interactions in one common framework. In terms of empirical precision, it is the most successful theory in the history of science. Physicists use it every day to calculate the aftermath of particle collisions, the synthesis of matter in the big bang, the extreme conditions inside atomic nuclei, and much besides. ...

Many physicists think that particles are not things at all but excitations in a quantum field, the modern successor of classical fields such as the magnetic field. But fields, too, are paradoxical.
If neither particles nor fields are fundamental, then what is? Some researchers think that the world, at root, does not consist of material things but of relations or of properties, such as mass, charge and spin.
There is nothing new here. From the earliest days of quantum mechanics, Bohr and other talked about a wave-particle duality. An electron is not exactly a wave or a particle, but a quantum that has properties of both, as well as other mysterious properties. The plural is quanta. The term is popular, as I see that Simons Science News Is Renamed Quanta Magazine.

Wednesday, July 17, 2013

Philosophy is dead

A new paper on Science and Philosophy: A Love-Hate Relationship argues:
In this paper I will argue that: (i) The natural sciences need philosophy; and (ii) That scientists need philosophy. ...

Stephen Hawking has declared the official ‘death’ of philosophy in a way that seems to echo Nietzsche’s famous phrase ‘God is dead’. Commenting on questions such as the behavior of the universe and the nature of reality, Hawking writes: “Traditionally these are questions for philosophy, but philosophy is dead. Philosophy has not kept up with modern developments in science, particularly physics. Scientists have become the bearers of the torch of discovery in our quest for knowledge.” (Hawking 2010, p. 5). ...

In this section I give two examples where philosophical discussion has been genuinely contributory to science, along the line s discussed in 3a)ii. Before doing that, I will address the negative examples that were given in 2b) — examples where philosophy’s influence has been rather hampering for science: the iron clad of mechanistic philosophy and Plato’s dictum that celestial motions should be along circles. ...

In the past ten years we have seen the first commercialization of quantum randomness: the first bank transaction built on the basis of a code encrypted not by the usual algorithms of classical cryptography (which rely on unproven mathematical assumptions such as the difficulty in factorizing large prime numbers), but based on the new field of quantum cryptography: a technique for encoding messages based on the notion of entanglement between particles at long distances. Quantum cryptography has been successfully developed and commercialized by several groups over the past twenty years or so.
No, this is just not true. There are no successful commercial applications of quantum cryptography. Philosophy has contributed nothing.

You can tell that this guy doesn't know what he is writing about when he says "difficulty in factorizing large prime numbers". Prime numbers do not have (non-trivial) factors. Only the non-prime numbers can be difficult to factor.

He also recites the usual nonsense about Kuhnian revolutions. Hawking is right. Philosophy is dead.

Monday, July 15, 2013

The Oxford Questions

A new published paper on The Oxford Questions on the foundations of quantum physics, by G. A. D. Briggs, J. N. Butterfield, A. Zeilinger, starts:
1. The achievements of twentieth century physics

Much of the history of twentieth century physics is the story of the consolidation of the relativity and quantum revolutions, with their basic postulates being applied ever more widely. It is possible to forget how contingent, indeed surprising, it is that the basic postulates of relativity and quantum theory have proved to be so successful in domains of application far beyond their original ones. Why should the new chronogeometry, introduced by Einstein’s special relativity in 1905 [1] for electromagnetism, be extendible to mechanics, thermodynamics and other fields of physics?

1. Einstein A. 1905 On the electrodynamics of moving bodies.
Ann. Phys.17, 891–921.
No, Einstein did not introduce a new chronogeometry in 1905. He used the Lorentz transformations with the same geometry as previously by Lorentz and Poincare. The geometry of time was introduced by Poincare in 1905, and popularized by Minkowski in 1908.

The article moves on to these questions:
The Oxford Questions.
(1) Time, irreversibility, entropy and information
(a) Is irreversibility fundamental for describing the classical world?
(b) How is irreversibility involved in quantum measurement?
(c) What can we learn about quantum physics by using the notion of information?

(2) The quantum–classical relationships
(a) Does the classical world emerge from the quantum, and if so which concepts
are needed to describe this emergence?
(b) How should we understand the transition from observation to informed action?
(c) How can a single-world realistic interpretation of quantum theory be
compatible with non-locality and special relativity?

(3) Experiments to probe the foundations of quantum physics
(a) What experiments can probe macroscopic superpositions, including tests of
Leggett–Garg inequalities?
(b) What experiments are useful for large complex systems, including technological
and biological?
(c) How can the progressive collapse of the wave function be experimentally

(4) Quantum physics in the landscape of theories
(a) What insights are to be gained from category-theoretic, informational,
geometric and operational approaches to formulating quantum theory?
(b) What are productive heuristics for revisions of quantum theory?
(c) How does quantum physics cohere with space–time and with mass–energy?

(5) Interaction with questions in philosophy
(a) How do different aspects of the notion of reality influence our assessment of the
different interpretations of quantum theory?
(b) How do different concepts of probability contribute to interpreting quantum
They claim that there has been progress in hidden-variables and many-worlds theories. I don't believe it.

Wednesday, July 10, 2013

Rovelli on free will

Physicist Carlo Rovelli writes:
Trying to force the meaning of "free will" beyond the simple meaning of freedom from "exterior" constraints, is an enterprise doomed to failure anyway. Is our "free" decision completely determined by internal factors? Let's assume for moment that it is not, and we see that we are in trouble. Suppose to be able to do an experiment where we can put a person in exactly the same mental situation (with the same memories, values, character, mood ...) and suppose we repeat the experiment many times, always with the same initial conditions. What would observe? There are two extreme possibilities: the first is that we see that the person will decide entirely at random. In this case the results will be just governed by chance. Half the time he will make a choice, the other half he will make the other choice. The second extreme possibility is that instead the person will always make the same choice.

In which of these two cases, is there free will?

Both answers are meaningles.
I mostly agree with this. Furthermore, those two cases are not the only ones. His thought experiment cannot be carried out, and we have good reasons to believe that it could never be carried out. It is a false dichotomy.
Any attempt to link this discussion to moral, ethical or legal issues, as is often been done, is pure nonsense. The fact that it is possible to say that a criminal has been driven to kill because of the ways in which Newton's laws have acted on the molecules of his body has nothing to do either with the opportunity of punishment, nor with the moral condemnation. ...

Free will has nothing to do with quantum mechanics. We are deeply unpredictable beings, like most macroscopic systems. There is no incompatibility between free will and microscopic determinism.
As I have noted before, quantum mechanics teaches that our naive preconceptions of microscopic determinism and randomness are both incorrect. To the extent that quantum mechanics is relevant, it rebuts the above dichotomy and also the one portrayed in this comic.

Monday, July 8, 2013

Relativity principle and covariance

Gomori and Szabo post a new paper on the meaning of the special principle of relativity (RP):
Let us illustrate this with only a few quotations:
“the laws of physical phenomena should be the same, whether for an observer fixed, or for an observer carried along in a uniform movement of translation” (Poincaré 1956, p. 167);
“If a system of coordinates K is chosen so that, in relation to it, physical laws hold good in their simplest form, the same laws hold good in relation to any other system of coordinates K0 moving in uniform translation relatively to K.” (Einstein 1923. p. 111);
“it is impossible to measure or detect the unaccelerated translatory motion of a system through free space or through any ether-like medium” (Tolman 1949, p. 12);
“all physical phenomena should have the same course of development in all system of inertia, and observers installed in different systems of inertia should thus as a result of their experiments arrive at the establishment of the same laws of nature” (Møller 1955, p. 4);
“the laws of Physics take the same mathematical form in all inertial frames” (Sardesai 2004, p. 1);
“The same laws of nature are true for all inertial observers.” (Madarász 2002, p. 84)
“The uniform translatory motion of any system can not be detected by an observer traveling with the system and making observations on it alone.” (Comstock 1909, p. 767);
“The laws of nature and the results of all experiments performed in a given frame of reference are independent of the translational motion of the system as a whole. More precisely, there exists a [...] set of equivalent Euclidean reference frames [...] in which all physical phenomena occur in an identical manner. (Jackson 1999, p. 517);
“If we express some law of physics using the quantities of one inertial frame of reference, the resulting statement of the law will be exactly the same in any other inertial frame of reference. [...] we write down exactly the same sentence to express the law in each inertial frame.” (Norton 2013);
“all inertial frames are equivalent for the performance of all physical experiments” (Rindler 2006, p. 12);
“the laws of physics are invariant under a change of inertial coordinate system” (Ibid., p. 40);
“The outcome of any physical experiment is the same when performed with identical initial conditions relative to any inertial coordinate system.” (Ibid.);
“experience teaches us that [...] all laws of physical nature which have been formulated with reference to a definite coordinate system are valid, in precisely the same form, when referred to another co-ordinate system which is in uniform rectilinear motion with respect to the first. [...] All physical events take place in any system in just the same way, whether the system is at rest or whether it is moving uniformly and rectilinearly.” (Schlick 1920, p. 10);
“laws must be Lorentz covariant. Lorentz covariance became synonymous with satisfaction of the principle of relativity” (Norton 1993, p. 796);
“The laws of physics don’t change, even for objects moving in inertial (constant speed) frames of reference.” (Zimmerman Jones and Robbins 2009, p. 84);
“the basic physical laws are the invariant relationships, the same for all observers” (Bohm 1996, p. viii);
“laws of physics must satisfy the requirement of being relationships of the same form, in every frame of reference” (Ibid. p. 54).
They end up settling on the definition used by Lorentz in 1895, and copied by Einstein in 1905. But then they note that it does not match the modern definition:
RP and the covariance of equations E are not equivalent — in contrast to what is so often claimed in the literature. As Norton (1993, p. 796) writes:
The lesson of Einsteins’s 1905 paper was simple and clear. To construct a physical theory that satisfied the principle of relativity of inertial motion, it was sufficient to ensure that it had a particular formal property: its laws must be Lorentz covariant. Lorentz covariance became synonymous with satisfaction of the principle of relativity of inertial motion and the whole theory itself, as Einstein (1940, p. 329) later declared:
The content of the restricted relativity theory can accordingly be summarized in one sentence: all natural laws must be so conditioned that they are covariant with respect to Lorentz transformations.
The term "relativity principle" and its popularization is from Poincare and his 1902 book. So his definition ought to be the controlling one. He then proved Lorentz covariance in 1905, and Minkowski used that as the basis of his 1908 spacetime theory. After that, everyone used covariance, and not the weaker Lorentz-Einstein condition.

Norton is a little misleading, because Einstein's 1905 paper said nothing about covariance, and only about the weaker Lorentz 1895 notion. It is true that Lorentz covariance became synonymous with satisfaction of the principle of relativity, but that is because Poincare proved it in 1905 and Minkowski popularized it in 1908.

The Lorentz principle, used by Einstein, was that the equations have the same form in different frames. Covariance means that the equations have a unified geometric meaning that automatically subsumes the equations for the different frames.

Strictly speaking, covariance is a mathematical principle and RP is a physical principle. Poincare wrote about the relativity of space, meaning that you can just measure distances relative to other points, and you cannot deduce an absolute coordinate for position in space. Likewise, the relativity of velocity says you cannot measure your absolute velocity. Covariance becomes a physical principle after variable are identified with physically measurable entities.

Einstein's 1905 relativity paper is one of the most famous science papers every written, and yet people are still getting it wrong a century later. As quoted above, he said "the same laws hold good". That is, the law in one frame has the same mathematical form as the law in another frame. Poincare made the superior statement that the laws "should be the same". The laws do not just look the same, they are the same. Einstein did not appreciate how covariance makes this stronger statement possible.

This is all detailed in my book, How Einstein Ruined Physics.

Friday, July 5, 2013

Quantum mechanics leaves possibility of free will

I believe that free will is a metaphysical issue, not a scientific one. Denying free will is foolish.

Hard-core determinist Jerry Coyne writes on the free will theorem:
I haven’t seen his formal treatment of the Free Will Theorem, so I can’t say I can evaluate it — much less understand it. From the interview it sounds simply like a refutation of pure physical determinism, which most of us who accept quantum mechanics don’t see as problematic. The question is whether our behaviors and “choices” can be influenced by quantum dynamics, but even if that were true it wouldn’t prove “free will” exists in any meaningful sense. But the proof of “free will” is also connected with the bizarre phenomenon of quantum entanglement.
One of his readers comments:
I think that we agree that everything is determined from the Big Bang

Not that I like it ~ I want a loophole to exist, but I can’t imagine what a legitimate [non-woo] loophole looks like. I would like it to be true that brains can control events, but brains would seem to be just a higher order implementation of fields, forces & particles.

The problem is that they cannot imagine quantum mechanics.

Physicist Matthew Leifer comments on my essay:
The so called "free will theorem" does not establish that particles have free will or exhibit genuine stochasticity, whatever those terms may mean. It is just another proof of Bell's theorem, pure and simple. Of course, Kochen and Conway do not conclude this, stating instead that measurement outcomes must be undetermined prior to measurement. However, they fail to note that this is incompatible with the other assumptions they have made. In particular, TWIN implies that measurement outcomes on the two wings have to be perfectly correlated and the only way this can happen in a hidden variable theory is if it is deterministic. Therefore, undetermined measurement outcomes is not an option unless you give up at least one of their other assumptions, with locality and realism being the obvious choices.
Maybe Kochen and Conway overstate their results, and they are really restating Bell's theorem. Regardless, quantum mechanics leaves open the possibility of free will.

I do not think that free will can be scientifically proved or disproved. But for those like Coyne who say it can be disproved, they ought to reconcile their supposed scientific beliefs with quantum mechanics.

Wednesday, July 3, 2013

Essay on quantum information

The 2013 FQXi FORUM: FQXi Essay Contest - It from Bit or Bit from It? asks:
The past century in fundamental physics has shown a steady progression away from thinking about physics, at its deepest level, as a description of material objects and their interactions, and towards physics as a description of the evolution of information about and in the physical world. Moreover, recent years have shown an explosion of interest at the nexus of physics and information, driven by the "information age" in which we live, and more importantly by developments in quantum information theory and computer science.

We must ask the question, though, is information truly fundamental or not? Can we realize John Wheeler’s dream, or is it unattainable? We ask: ”It From Bit or Bit From It?”
I submitted my essay, and there is discussion on the FQXi site.

I submitted an essay to last year's contest, and got a lot of favorable comments, but the judges picked other essays. I would think that if they thought that I said something wrong, then they would say so in the comments. I think that they have reasons other than the essay quality.

Monday, July 1, 2013

Thurston's philosophy of proof

I have posted about Henri Poincaré being way ahead of Einstein on relativity. He was also a leader in other areas of mathematical physics. But he was known more as a mathematician, as this essay describes one of his more famous papers:
Algebraic and differential topology have had several episodes of excessively theoretical work. In his history [D], Dieudonné dates the beginning of the field to Poincaré’s Analysis Situs in 1895. This “fascinating and exasperating paper” was extremely intuitive. In spite of its obvious importance it took fifteen or twenty years for real development to begin. Dieudonné expresses surprise at this slow start [D, p.36], but it seems an almost inevitable corollary of how it began: Poincaré claimed too much, proved too little, and his “reckless” methods could not be imitated. The result was a dead area which had to be sorted out before it could take off.
That essay stirred up trouble with this dig at a famous mathematician:
William Thurston’s “geometrization theorem” concerning structures on Haken three-manifolds is another often-cited example. A grand insight delivered with beautiful but insufficient hints, the proof was never fully published. For many investigators this unredeemed claim became a roadblock rather than an inspiration.
Thurston was very annoyed at this, and published a 1994 rebuttal:
About two or three years later, I proved the geometrization theorem for Haken manifolds. It was a hard theorem, and I spent a tremendous amount of effort thinking about it. When I completed the proof, I spent a lot more effort checking the proof, searching for difficulties and testing it against independent information. I’d like to spell out more what I mean when I say I proved this theorem. It meant that I had a clear and complete flow of ideas, including details, that withstood a great deal of scrutiny by myself and by others. Mathematicians have many different styles of thought. My style is not one of making broad sweeping but careless generalities, which are merely hints or inspirations: I make clear mental models, and I think things through. My proofs have turned out to be quite reliable. I have not had trouble backing up claims or producing details for things I have proven. I am good in detecting flaws in my own reasoning as well as in the reasoning of others. However, there is sometimes a huge expansion factor in translating from the encoding in my own thinking to something that can be conveyed to someone else. ...

What mathematicians most wanted and needed from me was to learn my ways of thinking, and not in fact to learn my proof of the geometrization conjecture for Haken manifolds. It is unlikely that the proof of the general geometrization conjecture will consist of pushing the same proof further.
I am not really sure what he is rebutting here, as Thurston seems to concede that he never published the proof. Nevertheless, Thurston's paper is famous, and UCLA mathematician Terry Tao just wrote that he would tag it as a "must read" for all research mathematicians.

Go ahead and read it, but keep in mind that Thurston was on the fringe of mathematics by denying the importance of a written proof. He was cited in a notorious 1993 SciAm article on the Death of Proof, and the author says he relied heavily on Thurston. Thurston was probably embarrassed by this paragraph:
Thurston emphasizes that he believes mathematical truths are discovered and not invented. But on the subject of proofs, he sounds less like a disciple of Plato than of Thomas S. Kuhn, the philosopher who argued in his 1962 book, The Structure of Scientific Revolutions, that scientific theories are accepted for social reasons rather than because they are in any objective sense “true.” “That mathematics reduces in principle to formal proofs is a shaky idea” peculiar to this century, Thurston asserts. “In practice, mathematicians prove theorems in a social context,” he says. “It is a socially conditioned body of knowledge and techniques.”
No mathematician wants to be associated with a Kuhnian paradigm shifter, so this paragraph surely also prompted Thurston's essay. Meanwhile, Thurston's geometrization conjecture has been proved in connection with the solution to the Poincaré conjecture. Yes, Poincare's analysis situs led to a century of research by the smartest people to solve it. And of course the mathematical community has published the proof several times over, even if some of the original provers left some gaps.