Quantum Fluctuation : Causal

Discussion in 'Physics & Math' started by The God, Mar 12, 2017.

  1. karenmansker HSIRI Registered Senior Member

    BTW: Nice response . . . I offer a comment, in a similar vein, that probing for observational evidence of the subquantum domain might look like a 'new physics' . . . . just sayin' . . . .
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  3. Randwolf Ignorance killed the cat Valued Senior Member

    Or the same old crackpottery - just sayin'

    At least you've let up on the plagiarizing lately:

    Is this an original quotation of yours, or have you plagiarized from an undocumented source . . . remember Sciforum rules!!

    Perhaps you should heed your own advice...

    karenmansker vs http://www.livescience.com/50326-what-is-ultraviolet-light.html
    Ultraviolet (UV) light falls in the range of the EM spectrum between visible light and X-rays. It has frequencies of about 8 × 1014 to 3 × 1016 cycles per second, or hertz (Hz), and wavelengths of about 380 nanometers (1.5 × 10−5 inches) to about 10 nm (4 × 10−7 inches).
    Ultraviolet (UV) light falls in the range of the EM spectrum between visible light and X-rays. It has frequencies of about 8 × 1014 to 3 × 1016 cycles per second, or hertz (Hz), and wavelengths of about 380 nanometers (1.5 × 10−5 inches) to about 10 nm (4 × 10−7 inches).

    karenmansker vs https://en.wikipedia.org/wiki/Infrared
    Infrared radiation extends from the nominal red edge of the visible spectrum at 700 nanometers (nm) to 1 mm. This range of wavelengths corresponds to a frequency range of approximately 430 THz down to 300 GHz. Below infrared is the microwave portion of the electromagnetic spectrum.
    Infrared radiation extends from the nominal red edge of the visible spectrum at 700 nanometers (nm) to 1 mm. This range of wavelengths corresponds to a frequency range of approximately 430 THz down to 300 GHz. Below infrared is the microwave portion of the electromagnetic spectrum.​

    karenmansker vs http://www.physicsmatters.org/quantum/ehv.html
    E=hv: This equation says that the energy of a particle of light (E), called a photon, is proportional to its frequency (v), by a constant factor (h). This means that photons with low frequencies, like radio waves, have lower energies than photons with high frequencies, like x-rays.
    E=hv This equation says that the energy of a particle of light (E), called a photon, is proportional to its frequency (), by a constant factor (h). This means that photons with low frequencies, like radio waves, have lower energies than photons with high frequencies, like x-rays.​
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  5. karenmansker HSIRI Registered Senior Member

    HAHAHA! (Source: plagiarized from previous KSM posts and your prior post about it elsewhere) . . . . Randwolf . . . . you REALLY need to get a life!
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  7. rpenner Fully Wired Staff Member

    That came from your lack of reading comprehension, either natural or because you have a cognitive bias.
  8. rpenner Fully Wired Staff Member

    “Just sayin'” is not a concrete claim so it isn't worthy of consideration. You are following exactly the road map I sketched of someone who was dooming themselves to be a physics outsider:
    Indeed, the phrasing "subquantum domain" suggests you have elevated a specific fringe idea to be a personal axiom, yet cannot convince anyone of the worth of such preconceptions.

    Both my English exposition and formulae tend to be 100% original works derived from acquaintance with underlying theory. Math and physics always go hand-in-hand since precision is vital to knowing if you are on the right track. When some math is esoteric such as computing Clebsch–Gordan coefficients or elements of Keplerian orbits from first principles, I prefer to link to references so that less exposition is required.

    Cassius Jackson Keyser wrote: “As an enterprise mathematics is characterized by its aim, and its aim is to think rigorously whatever is rigorously thinkable or whatever may become rigorously thinkable in course of the upward striving and refining evolution of ideas. As a body of achievements mathematics consists of all the results that have come, in the course of the centuries, from the prosecution of that enterprise: the truth discovered by it; the doctrines created by it; the influence of these, through their applications and their beauty, upon the advancement of civilizations and the weal of man.” in "The Human Worth of Rigorous Thinking" (1916).

    Thus is it natural for physicists to master some mathematics. The math of linear algebra becomes the math of multivariable calculus and then differential geometry in arbitrary curvilinear coordinates with utility for physics at every step along the way. Other math like considering generic forms of symmetry seem very abstract until it is discovered that every continuous symmetry in the laws of physics gives rise to a conservation law which is perfect if the symmetry is.

    GR is uncontradicted by observation. Human logic says quantum physics and general relativity (as we understand them today) cannot co-exist because the unification of quantum physics of point particle and special relativity is quantum field theory which has problems doing spin-2 fields. It sounds like you favor QM over GR while KSM disfavors QM, but neither position is justified by science. String theory, for example, hopes to preserve both with the point-like nature of quantum particles being retired. Loop quantum gravity changes the meaning of space-time. The replacements for QM are harder to describe except for Bohmian Mechanics, which seems more like sleight-of-hand with probability currents than a novel physical theory to me.
    Last edited: Mar 22, 2017
  9. exchemist Valued Senior Member

    Of course he's not saying that. Rpenner, as I know from previous discussions, is very well aware that what we make in science are models of reality and cannot be presumed to be reality.

    Nevertheless, Ockham's Razor is applied. In other words there is only reason to construct further hypotheses when there is observational evidence that they are required. He is saying there is no such evidence at present.

    Nobody is remotely suggesting we should stop looking. That suggestion is an Aunt Sally.

    (Educated people stopped thinking the earth was flat in about 300BC.)
    Last edited: Mar 22, 2017
  10. Schmelzer Valued Senior Member

    The theory would, indeed,"had better also respect that symmetry". In the sense that we would prefer a theory which has this symmetry to a theory which does not have it, everything else being equal.

    But if there is no "everything else being equal", but to preserve the symmetry we have to give up such obvious things like realism (in the variant of the EPR criterion of reality) and causality (in a variant containing Reichenbach's common cause principle) then everything else is not equal. Or if we have to reject the natural interpretation of one part of the Schrödinger equation as describing a continuity equation for the probability flow, because the velocity formula for this flow would violate Einstein causality.

    No. The leading interpretations of quantum theory reject determinism, but determinism is compatible with quantum theory and observation, as shown by de Broglie-Bohm theory, which is deterministic, but gives in some special states, named quantum equilibrium, the same probabilistic predictions as quantum theory.

    And the result could have been completely different - at least for the way it is presented to laymen.

    An alternative history of physics - with the same real physics behind it:

    1.) The mathematics of Lorentz transformations are found a little bit earlier. As a nice mathematical trick to construct a large number of new solutions to the Maxwell equations from a given solution.
    2.) Instead of trying to explain MMX-like effects with the idea that matter is hold together by EM forces, and that this could explain that matter (and therefore clocks and rulers) follow the same symmetry as the EM equations, he would have thought about this hypothesis earlier, and, given that the method above was already known, would have proposed that it can be used to test the hypothesis that it is EM force which holds matter together: In this case, a Lorentz-transformed solution for a piece of matter would be also a solution of the same equations for matter. But that means that a Lorentz-transformed solution for a clock at rest would run slower, and MMX would have been predicted.
    3.) Motivated by this nice trick, other mathematicians would find other wave equations where the same Lorentz transformations also allow to construct new solutions. This would have been used to say that the MMX is not decisive to prove that the forces which hold matter together are EM forces, they could be other forces, essentially all they should do is to follow a wave equation with the same limiting speed of the waves.
    4.) Together with one geometric example, which shows the limitations of measurements of distances to identify the true geometry, Poincare would have used also Lorentz symmetry to show that humans cannot use measurements to identify even what happens on equal time. So, something which obviously exists (contemporaneity between far away events) cannot be measured because our clocks are distorted if they move against the ether. This would have been accepted as an interesting curiosity and otherwise widely ignored.
    5.) Minkowski would have, nonetheless, proposed his "spacetime interpretation". In the following discussion between spacetime and ether proponents, there would have been found agreement that the theory of gravity, which actually is known to have a larger speed than c, contradicts the spacetime hypothesis. The spacetime proponents would have, instead, used the argument that for an ether the wave equation can only be an approximation, where the ether is incompressible and ideally rigid, and violates the action equals reaction principle, while such an ideal, exact symmetry would be a characteristic of a spacetime interpretation, which
    6.) A discussion about gravity starts: What causes gravity, in modern terms rest mass or relativistic mass? The old scalar theory can be shown to be invalid, new theories with the momentum vector as well as with the energy-momentum tensor as the source of gravity appear. Einstein shows with his equivalence principle that a theory with energy-momentum tensor as the source of gravity would be fine. And that it would be, in the light of discussion (5), compatible with an ether theory, with the gravitational field described by an energy-momentum tensor of the ether.
    7.) The mathematics of GR in harmonic coordinates will be developed as the theory of evolution of that ether.
    8.) The public only learns that ether theory has developed very well, and that the observation of deflection of light was the final proof of the existence of an inhomogeneous ether.
    9.) Quantum theory develops as usual. Except that the Schrödinger equation is interpreted as describing a continuity equation for the probability flow and a generalization of the Hamilton-Jacobi equation.
    10.) Together with the uncertainty relations, found only for configuration vs. momentum, it is observed that there is no self-adjoint operator for time measurement, thus, exact absolute time is unobservable.
    11.) Given that there is a continuity equation for the configuration, nobody doubts that a trajectory in configuration space exists. Nobody makes stupid claims about quantum logic or impossibilities of such trajectories or so. The public never hears about quantum strangeness, except in history of science about a short period of crisis before quantum theory has been found.
  11. Schmelzer Valued Senior Member

    Rereading the text I see some errors, unfortunately to late to edit them away:
    In (2.) he -> Lorentz
    after (5.) which would predict that light in vacuum would always move along straight lines.
    after (7.) with the ether density $g^{00}\sqrt{-g}$ and the ether velocity $g^{0i}/g^{00}$ so that the harmonic equations become continuity and Euler equations for the ether.
  12. pluto2 Registered Senior Member

    My point was that scientists think they know everything but in reality they really know very little.

    Scientists can't even figure out how the human body (and brain) works or why we sleep, why we feel pain (and why some people don't feel pain) and many other questions and puzzles.

    I think that scientists are still very very far away from figuring out everything there is to know.

    Last edited: Mar 22, 2017
  13. The God Valued Senior Member


    Spin and metaphysics....
    Spin and prediction...

    Both are by you only, so onus is on you to state how a metaphysical entity can be predicted.
  14. exchemist Valued Senior Member

    Now you are making things up. We went into intrinsic angular momentum, known as "spin" for short, at length on a previous thread. Nobody but you thinks it is "metaphysical" concept. We pointed out it is anything but metaphysical: it is an empirically observed phenomenon, which is modelled, apparently accurately, in QM. That is physics, not "metaphysics.

    The fact that it cannot be well modelled by a classical mechanical analogy, such as a little spinning ball, does not in any way lessen its objective physicality.
  15. The God Valued Senior Member


    The reference to metaphysics was by rpenner in that spin thread. ..

    an empirically observed property cannot be metaphyisical.....and a metaphysical entity cannot be predicted

    I came out of that thread after referring to swetlana's spinning as metaphysical in lighter vein.
    Last edited: Mar 23, 2017
  16. The God Valued Senior Member

    Yes, it does. That's precisely what I am saying.

    'Spin' is always taken as a classical entity, the original reference even while defining spin in context with splitting of spectral lines in Zeeman effect was in classical sense. But later on it created problem...so wriggling out.
  17. rpenner Fully Wired Staff Member

    Angular momentum, energy and momentum date back to classical mechanics, indeed they relate to the symmetries of Euclidean rotation, time-translation symmetry and position-translation symmetry that are common to many physical theories, but their representations and formulae have changed in light of quantum mechanics and relativity to better reflect the behavior of observable phenomena.

    You may be abusing terminology because it looks like when you say "spin" you mean angular momentum while a physicist would distinguish between orbital angular momentum and intrinsic angular momentum. One of the big differences is that measurement of the first is quantized (in bound systems) in units of ℏ and is independent of the type of particle while the other is quantized in multiples of ½ℏ and the type found is determined by type of particle. And the type of intrinsic angular momentum (spin, in the correct physics jargon) relates to how collections of identical particles behave. Intrinsic angular momentum does not have the same relation with the magnetic momentum of an electrically charged particle as does orbital angular momentum. For the electron, the difference is a bit more than a factor of 2. Thus the type of intrinsic angular momentum (spin-0, spin-1/2, spin-1, spin-3/2, etc) is an important part of describing particles and even bound systems when the energy scale of interactions is too low to probe their interior structure. Superfluid helium-4 and the phenomenon of lasers relate to the behavior of bosons while the fact that neutron stars hold up against gravitational collapse relates to the sermonic nature of neutrons.

    Classical physics knew only of orbital angular momentum but because the six-parameter Lorentz group in 3+1 spacetime means Lorentz boosts and Euclidean rotations relate to each other in specific ways, both the phenomena of intrinsic angular momentum and the relation between intrinsic angular momentum and behavior of collections of identical particles follow from first principles.
  18. exchemist Valued Senior Member

    I do wish you would not use pejorative terms like "wriggling out". It falsely suggests some kind of intellectual dishonesty. What happened was people learnt more.

    All the QM concept of intrinsic angular momentum does is adapt theory to fit observation, without imposing man-made preconceptions. That is what science should do. You, if I may say so, seem to be displaying a lack of capacity to set aside your own preconceptions, apparently because you have a classical idea in your head of what "spin" should look like - and therefore you "feel" there is something "wrong" or unsatisfactory about what QM says about it. That is your problem, not science's.

    Rpenner's comment about metaphysics related to another question, namely what intrinsic angular momentum "really is". That appeared to be a question about ultimate reality, rather than about the models of reality that we build in science, and that is why it was described as a metaphysical issue. More here: https://en.wikipedia.org/wiki/Metaphysics

    This discussion exposes a profound - and often overlooked or misunderstood - philosophical point about the nature of science. Science seeks explanations of how the physical world behaves, that enable us to predict what we should observe. But it deals in models which cannot claim to be ultimate reality, as they can always in principle be shown wrong or incomplete by new types of observation. This eternally provisional nature of science means that it can never tell you what something "really is": all it can do is tell you how we think it behaves, to the best of current knowledge.

    You are perfectly entitled to feel there is something incomplete about QM. That is the attitude we should keep at the back of our minds, with all theories in science, due to their inherently provisional nature. However, when we have a theory that fits all the current observations, we can at least say there is no need for further change to the model for the time being.
  19. The God Valued Senior Member


    Wriggling out as such is not pejorative, because in many theories, we do use so called fudge factors or factors of convenience.

    When we present a theory, the foremost is definitions. Can we tweak with the definition?
  20. rpenner Fully Wired Staff Member

    Wriggling out is pejorative. Fudge factors are pejorative. This is widely recognized by people who know English.
    http://www.macmillandictionary.com/us/dictionary/american/wriggle-out-of-doing-something “[phrase] [showing disapproval] to avoiding something by making excuses”
    https://en.wiktionary.org/wiki/fudge_factor “A quantity introduced to compensate for uncertainty. // any padding or compensation built into a guess or estimate”

    Fundamental physical theories have no fudge factors because they predict precise behavior. Most are written in the form of equations which also don't have fudge factors.
    Experimental physics deals with the uncertainty of measurement and statistical sampling and human error. Astronomy is particular rife with uncertainties as we don't have the option of viewing the stars from another vantage point, such that distances and ages used to have ugly paradoxical results. Learning to deal with uncertainty, to quantify it and describe it is part of the language of experimental physics.
    Engineering models do have fudge factors because they have to solve a specific problem even in the face of uncertainty, so they deliberately include margins of error so projects don't fail because parts don't fit together as precisely as would be ideal. In contrast, if the equations of a physical theory can be shown to not hold exactly, the theory is busted.
    When it is a different theory, absolutely yes. Nothing about definitions of terms in physics makes sense except in light of the theoretical model. Introduction of a new model means potentially new definitions, because a new physical model is a new way of thinking about the behavior of phenomena so what was fundamental in one model might not be in the successor. And this new thinking is not limited to the people who propose the models. Indeed, Newton did not come up with kinetic energy and Einstein did not come up with the geometry space-time even though these ideas spring from the way they modeled the behavior of the universe.
  21. The God Valued Senior Member

    You have chosen the convenient meaning of wriggle out. It means to avoid or to get out of too. Anyways, let's not get into English here.

    As far as holding of maths is concerned, pl recall first we talked of expansion of universe, till around 1998, and then it became accelerated expansion. And the best part is Einstein, the founder of theory, did not know about both when he proposed this theory.

    And are you saying that science has no fudge factors?!
  22. karenmansker HSIRI Registered Senior Member

    " . . . . Fundamental physical theories have no fudge factors because they predict precise behavior. Most are written in the form of equations which also don't have fudge factors." . . . .

    fudge factor: Renormalization?
  23. rpenner Fully Wired Staff Member

    That was not a change in math, but a change in a description of the evolution of the universe based on observation. The equations for the GR-modeled expansion of the universe always supported universes that collapse and universes with runaway expansion depending on what the content of the universe was.

    Einstein introduced 1-parameter General Relativity (1916) and at a time when the Milky Way was presumed to be the whole universe Einstein introduced 2-parameter General Relativity (1917) to explain why the galaxy/universe was stable. The wrong solution, in response to a human bias, solving the wrong problem, could be called a fudge factor. http://scienceblogs.com/startswithabang/2013/05/17/einsteins-greatest-blunder-was-really-a-blunder/
    See also the pop cosmology book : Einstein's Greatest Blunder?: The Cosmological Constant and Other Fudge Factors in the Physics of the Universe (1997). Which is an indictment of the wide error margins of astronomical observation from 20 years ago.

    But the math behind 2-parameter General Relativity is sound. And in current models of ΛCDM cosmologies, we don't have evidence which lets us distinguish between a non-zero cosmological constant of 2-parameter General Relativity or a unknown component of this universe "Dark energy" with a certain equation of state and 1-parameter General Relativity. In this sense, divorced from Einstein's biases and aesthetics, 1-parameter General Relativity and 2-parameter General Relativity are competing descriptions of gravity, but we need more information to chose between them because it is unclear if gravity or the content of the universe gives rise to the flatness of the universe where matter and dark matter combined fall short to explain by a factor of more than 3.

    Observation science describes and manages uncertainty in measurement. Physical theories have free parameters which must be fitted to all observations. As such the fitted parameters will have margins of error because the underlying observations introduce errors, bias and uncertainty. So its possible for a wrong theory to persist, living within the error margin. So science continues to refine experiment and observation to make those margins shrink leading to the death of theories which are incompatible with the totality of observation. Now most of the charges in the 20-year-old book are antique due to progress on multiple fronts.

    You pretty much made this "fudge factor" slur out of your personal misunderstanding of the nature and practice of science. Here you are in a time of progress in cosmology and you belabor old gaffes and misunderstandings.

    Renormalization is not a fudge factor. It is a calculation technique which exists because the perturbative expansion of quantum field theories have certain features (an explosion of degrees of freedom because E=mc² so simpler ways of computing things get computationally unwieldy if large amounts of momentum get involved) which lend themselves to analytical manipulation of the formally unbounded degrees of freedom at high energy scales.
    It's not a fudge factor any more than \( \sum_{k=1}^{\infty} \frac{1}{k^2 + k} = \lim_{n \to \infty} \sum_{k=1}^{n} \frac{1}{k^2 + k} = \lim_{n \to \infty} \frac{n}{n+1} = 1\) is a fudge factor. The theory stays the same, the equal signs retain their meaning, the only difference is that we are able to calculate quantities that relate theory to observables. rather than giving up because math is hard.

    As a math and physics outsider, how are you in a position to judge the math of interacting relativistic quantum fields?
    Last edited: Mar 23, 2017

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