Observers

Discussion in 'Physics & Math' started by arfa brane, Apr 18, 2017.

  1. arfa brane call me arf Valued Senior Member

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    Well, not really. Time isn't something we can say "is zero", but we can define an arbitrary point in time and say it's where t = 0, that is, identify a reference point.

    Now I know there are all kinds of philosophical problems with points of space or time, because these can't be shown to actually exist via any measurements.
    Nonetheless, if there is a continuum, and if differential calculus is an accurate picture of physical reality, then points exist because limits exist.
    It can't be the basis of time (whatever that is). Entanglement exists because particles interact at some time, then remain entangled as long as they don't interact with any other particles. This implies that non-interaction of entangled particles preserves entanglement over . . . time (!) You can't formulate a theory of entanglement being "the basis" of time if it still needs external clocks (now can you?).
    Sorry, I can't really parse that.
    Minkowski knew nothing about the so-called spooky action (which as has been pointed out to you, is not action, but correlation following measurement).
     
    Last edited: Jun 19, 2017
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  3. danshawen Valued Senior Member

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    Bound energy that is matter, antimatter persists in time, which is exactly what you just said. Why is that? What force is responsible for doing that, if an instantaneous force such as hansda suggested does not exist? Entanglement works differently for bound, unbound energy. For bound energy, it is literally what allows it to persist with respect to time. For unbound energy, or for bound energy with a relative velocity of 0.999999... x c, it means time does not "stop" literally either. Entanglement is the reason.

    You evidently agree, because now you are framing the idea exactly the way I am.

    Even the invariant speed of light, as measured in any inertial frame of reference, must be measured relative to something else that is invariant. That something else is the quantum field in which the instant of now makes sense, and is faster ("slower") than the speed of light.

    FROM THE POINT OF VIEW OF A PHOTON, IT IS THE REST FRAME THAT IS TRAVELING AT A SPEED OF - c. Would that be "faster", or is it "slower"?

    Does that "parse"?

    True. And this is exactly why, Mr. Minkowski could not possibly have understood the relativity of simultanaeity at all.

    Replace Minkowski's "two simultaneous events" with a pair of electrons or photons exchanging quantum spin states. Minkowski spacetime disappears. Minkowski rotation disappears. Minkowski intervals and light cones no longer make any sense at all. Minkowski could not have cared less; he was an 19th century mathematician obsessed with applying the spendor of quadradics and classic greek geometry to relate space to time, not a 21st centrury physicist. He almost pulled it off. Almost.
     
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  5. Q-reeus Banned Valued Senior Member

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    No. How many times will you continue to spout such nonsense, in CAPITALIZED SHOUTING TEXT no less? There can be no such thing as 'the point of view of a photon' since 'being in the frame of a photon' is impossible even in principle. Which well known fact has been brought up many times yet never penetrates the skulls of some (maybe most) memebers here. One example: http://www.sciforums.com/threads/time-dilation-of-photon-vs-wave-movements.156116/#post-3375692
     
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  7. The God Valued Senior Member

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    Neither.

    Interference is not a quantum thing, the way you are making this statement.

    And there is no such animal called negative amplitude. Do not trivialize the superimposition concept.
     
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  8. arfa brane call me arf Valued Senior Member

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  9. arfa brane call me arf Valued Senior Member

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    Ok, I see I made the mistake of omitting the word "amplitudes", in the phrase "probabilities are complex valued". The amplitudes are complex-valued, but the 2-norm is real.
    Oh. Ok. In what way is interference ever a quantum thing then?
    But there is. It's why destructive interference occurs.
    Perhaps you have another explanation for interference patterns seen in double-slit experiments?
     
  10. The God Valued Senior Member

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    I can figure out that you are doing a lot of reading on Quantum Computations. This is taking you through all sort of weirdo writings by many authors and you are facing natural parsing problem.
     
  11. The God Valued Senior Member

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    I will respond to amplitude being non negative. Consider the simplest form of a wave at any instant, it can be expressed as A*Sin(x) where x can be anything between 0 to 2pi. This 'A' is amplitude which is a positive value, ASinx could be negative depending on value of 'x'. Interference is not of two 'A's.

    Edit : 'A' is the peak amplitude value, and amplitude at any instant will be less than that depending on value of Sinx. The negative values shall be due to phase aspect.
     
    Last edited: Jun 19, 2017
  12. Q-reeus Banned Valued Senior Member

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    Aaronson for some reason deliberately overstates there the case for QM = statistics with complex amplitudes. Neither the de Broglie relation or PEP (Pauli exclusion principle) are statistical in character at all yet without them there would be no chemistry, no electron microscopy, no white dwarfs or neutron stars held up by degeneracy pressure, etc etc..
     
  13. arfa brane call me arf Valued Senior Member

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    I can agree with that to some extent. But, he says this near the top of the page:
    This is right after he says:
    He does seem to be saying that QM isn't a physical theory, because it's about quantum probabilities (complex amplitudes). He even does a fairly heroic job of explaining why the amplitudes are complex, not real or quaternionic.

    And about the deBroglie relation, electron degeneracy etc. I don't know you can say these aren't statistical. I don't know you can say any physics is not statistical, actually.
     
  14. exchemist Valued Senior Member

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    12,451
    From the look of it, this term is the source of some of the misunderstanding between Arfa and The God. Arfa acknowledges he left the word "amplitude" out of his statement about probability and complex values. It makes perfect sense to speak of a complex-valued probability amplitude, but The God is quite right that actual probability values must be real.

    One can regard the amplitude of the wavefunction as a "probability amplitude", as its square modulus is a probability density.

    This is by analogy with classical waves, in which one takes the square modulus of the amplitude to get the intensity of the energy transmitted by the wave. The square mod of the wavefunction amplitude is the "intensity" of the probability at that point in space.

    Further reading about intensity here: https://en.wikipedia.org/wiki/Intensity_(physics)
     
  15. Q-reeus Banned Valued Senior Member

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    The two mentioned QM principles in #209 have nothing statistical about them per se, but of course statistics enters when embodied in actual many-body physical systems e.g. PEP is fundamental to Fermi-Dirac statistics applied in solid-state physics, say conduction bands in metals.
     
  16. exchemist Valued Senior Member

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    Not really sure what your questions mean here.

    "Information" about probability is obviously present in the wave function and this information is "real", in the sense that it is not bogus. However it is contained in a complex function. As you know, to get any physical observable out of a wave function you have to operate on it mathematically in a way that produces a real, as opposed to complex or imaginary, output. But then you have something a bit like this with AC theory, don't you?

    I don't think I understand what you are getting at by asking whether the Schroedinger equation is "about" measurement. It seems to me it is "about" representing a "particle" as a "wave", in order to account for observed phenomena such as spectral lines, the structure of the atom etc. It seems to me this makes it "about" a model of physical reality. The measurement stuff follows from this type of representation, sure, but I don't see that that is what it is "about".
     
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  17. exchemist Valued Senior Member

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    Yes, I'd say they are both wavelike in origin but not statistical per se. PEP is the result of a multi-"particle" wave function being antisymmetric on particle exchange, which is a symmetry property of the wavelike nature of (fermionic) matter, but that is not a statistical argument, it seems to me.
     
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  18. arfa brane call me arf Valued Senior Member

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    Some people might have read about entanglement being the reason the universe appears to have three dimensions (to observers like us, that is); the third dimension or depth is emergent. Some might have read about entanglement also being the reason time emerges.

    Check out this article: https://www.scientificamerican.com/article/tangled-up-in-spacetime/
     
  19. arfa brane call me arf Valued Senior Member

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    7,832
    Or, alternatively, the information is present when a wavefunction is measured, otherwise nothing objective can be said about the wavefunction or if it's real. This is in line with whether real probabilities are objectively real, or only real in the sense of what is or can be (statistically) known about some system.
    Well, it isn't about measurement, not at all. And yet we measure something.
     
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  20. exchemist Valued Senior Member

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    I don't buy that. One does not measure a wave function, after all.

    A wave function is the mathematical expression one writes down to model a QM entity. This - indisputably - contains information about what one can expect from a measurement. But one measures the QM entity.
     
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  21. danshawen Valued Senior Member

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    Fine. But there CAN be a "point of view" from US, RIGHT NOW, relative to an observer on the red shifted far side of the observable universe, because we are moving relativistically relative to them right here, right now. They see time dilation relative to them. We see time dilation relative to us.

    And there definitely is, or would be twin paradox relative TIME DILATION here with respect to them, unless we had started moving apart symmetrically and simultaneously from the era of the Big Bang, and then were somehow brought back together at equal relative velocities.

    In this way, the universe reveals its symmetry with respect to time, a symmetry which Minkowski spacetime doesn't quite capture because it divided by zero before the entanglement version of simultanaeity was even known. Entanglement, not the invariant velocity of light, is what makes time dilation symmetrical/assymetrical across the known universe like that.
     
  22. danshawen Valued Senior Member

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    Articles like this the one by senior scientific american editor Clara Moscowitz are the reason I stopped subscribing to scientific american a very long time ago. I don't think some of the articles are edited by someone more knowledgable than this senior editor, much less peer reviewed.

    Qubits inside of black holes? Why would anyone care? Nothing entangled with anything else inside will ever leave as information in cosmological time.

    "Because finding a working theory of quantum gravity is so hard, the thinking goes, physicists could aim to discover an equivalent, easier-to-work-with theory that operates in a universe with fewer dimensions than ours."

    "Ours" has only one dimension. That dimension is time, in every direction, and energy transfer events that depend on it. Gravity is such an energy transfer event, even if we do not understand anything about it execept how someone with a math degree can simulate how it behaves using a universal gravitational constant that is nothing more or less than an unexplainable fudge factor that allows you to do your proportional math on something else you don't really understand.

    A hologram is a representation of a representation, just as math is a pared down symbolic shell of reality necessary for finite minds that cannot cognate all of the truth of reality at one time. When you do math and perform such a reductionist process on reality, you only get something that must of its own nature be incomplete or inconsistent. Reality is neither, because it doesn't have to be. Reality's symbols are the actual things we need to reduce to create symbols that will fit into conceptual categories within our finite minds. A symbol is not a thing.

    The correction of Minkowski's divide by zero error to restore time as the supreme dimension of which space ("light travel time") is only an artifact. Combined with hansda's instantaneous revision of Newton's laws of motion to include forces due to entanglement, these are the beginnings of a working unified field theory that include the reason the universe has bound, unbound forms of energy, and how time relates to different forms of energy to preserve the conservation of mass/energy.

    A unified field theory unites all of the forces of nature. You cannot have one of those unless you understand all of those forces, and that requires a model for time itself that is not an artifact of a proportional division by zero to create an interval of a mangled understanding of light travel time combined with time, facilitated by a classical greek Euclidean Pythagorean complex solid geometry haphazardly and inconsistently grafted onto another one of those absolute version of inertialess space. Absolute space never existed. Absolute time does.

    Truth be told, we already have the requisite unified field theory. It is the law of conservation of mass/energy, which all of the forces of nature already obey. Only entanglement as an instantaneous force was left out, and that's a shame, because without it, the other forces won't really make sense either.
     
    Last edited: Jun 19, 2017
  23. Q-reeus Banned Valued Senior Member

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    In standard FLRW metric, and neglecting any cosmological scale minor statistical 'peculiar velocities', there IS symmetry of motions.
    Huh? I cannot recall you ever even explaining let alone justifying this oft repeated claim of Minkowski's 'grievous divide by zero error'. The standard 4D line element is a backbone of SR, much used in GR, but once again you reproduced a fundamentally incorrect, elliptical geometry 'version' of it in #200. It pays to at least represent correctly the basic form Minkowski developed, before criticizing it, yes? No need to answer that btw Dan.
     
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