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joigus

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joigus last won the day on November 17

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About joigus

  • Birthday 05/04/1965

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    Biology, Chemistry, Physics
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    Physics
  • Favorite Area of Science
    Theoretical Physics
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    I was born, then I started learning. I'm still learning.
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    teacher

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  1. Meaning "from behaviour of visible matter around them."
  2. Reverse-image search produced this: https://www.cam.ac.uk/research/news/black-hole-powered-jets-fuel-star-formation It seems to be the result of a super-massive BH swallowing a region of star formation and producing as a result a pair of powerful jets of ejected material. The central bright region is probably the accretion disk of said BH. Not every spot of light is the BH. Black holes can't be seen directly. You can infer their position from gravitational lensing or from behaviour of matter around them.
  3. https://en.wikipedia.org/wiki/Measure_(mathematics) https://en.wikipedia.org/wiki/Fractal Hausdorff measure (fractals): https://en.wikipedia.org/wiki/Hausdorff_measure I hope that helps.
  4. (Emphasis mine.) What do you mean??? Here's a visual aid: Same particles, same events for time-like separated particles. And, Same particles, same events for space-like separated particles. What light cone are you talking about? Same light cone of what exactly? Will you make a smidgen of sense at some point in this simulation of a discussion? I'm ignoring the rest of your nonsense. Let's start with the basics. Otherwise, you're gonna turn everyone crazy here. "Especially electrons..." Yeah, that makes sense too!
  5. Same reason why the colour of my sclera, and the colour of yours are the same: Some event in the past determined both. In the example I'm offering you, the evolution of a family of primates. Unless one of us is a possum who's learned to type. Let that be me. Oh, by the way, I've just received a message from next Christmas: Our future selves tell me we are still discussing this.
  6. I think Markus meant "measure" in general. There are many cute puzzles like this that are similar and involve other kinds of measures, like Hilbert's curve covering a patch of plane. On the other hand, mathematics based on natural numbers is known to be incomplete, and no theory of this kind can prove its own consistency, so I would relax about the whole thing. Besides, there is no unified set of axioms for all of mathematics, as far as I know. You can relate chunks of it, but not all. I would relax even more. I may be wrong, but I think in this post-Bourbaki era mathematicians tend to be more freely constructive and more deeply involved in guesswork. This has proved to be very fruitful for both physics and mathematics.
  7. What particular physical aspect of the round house kick do you want to understand by means of the moment of inertia? If you want to totally understand the theory of the moment of inertia, you need some integral calculus (although you can do without much) and some vector algebra (perhaps a bit more than calculus.) But qualitative discussion of some simple cases can be done without big mathematical hurdles.
  8. It absolutely is not a non-local Lagrangian. Let me rephrase without the double negative, which might be confusing: The Lagrangian is totally local. Once the particles start flying apart, you can use free propagation to describe how the fly apart, and the initial entangled state as the initial condition of a so-called Cauchy problem. The Hamiltonian is separable, and contains only 2nd-order spatial derivatives, so local densities, fields, etc are only sensitive to nearby points. It is a 2nd-order polynomial in the spatial derivatives. Local as can be: Exactly the same sensitivity to spatial inhomogeneities as the equation for propagation of heat. And the state keeps entangled all the way. What the classical theory of heat doesn't have, that makes quantum mechanics so peculiar, is, 1) Superposition of several different "heat-radiating states" 2) A multi-system phase space It is the initial condition that cannot be separated, which has consequences on the probabilities that are encapsulated in the state. As Markus said --with my emphasis, Which is exactly what I was trying to say here, This, by the way, you found either very surprising, or implying the opposite of what @Markus Hanke --and I too, many pages before-- is implying: As the probability distributions do not depend on spatial factors while the state is evolving, as it only depends on how the state is interwoven in its spin "tags," how could it encode anything having to do with local (space) properties? Or at least, that is, provided I've understood Markus correctly.
  9. The discussion was actually about FTL signals. More in particular, it assumed that FTL signals are actually implied by quantum entanglement. From that as a premise, it proposed the possibility that this "entangled information," whatever that means, can be somehow amplified, or "crowded." It was I who first challenged the premise that FTL signals are possible from the mere basis of QM. @uncool then proposed whether it could be the breaking of quantum coherence --or, if you will, the collapse of the wave function-- that could be used as a signal. Here: That was a very interesting point. I think I basically answered this with a clear resounding "no." But at this point the debate was getting, IMO, very interesting. Then you intervened by entering into a dynamics of a dog chasing his own tail, by repeatedly denying matters of principle and experimental evidence that nobody else here has any significant doubt about. As long as you do not agree on these matters of principle, it will be impossible to further understand why this illusion of non-locality --that's implied, eg, in the last paragraph you quoted-- occurs when one thinks of QM in the terms of Copenhagen's interpretation of the theory. I did try to steer the debate in that direction, because I think it explains the confusion as close as effortlessly as it's possible to do. You stubbornly repeated asking me for a criterion of non-locality after, many posts before, I had already given you one: That you either didn't understand or didn't bother to read. For a theory to actually be non-local, it would have to be a system that, once cast in a Lagrangian form, would have an infinite sensitivity to spatial inhomogeneities. This would reflect in the Lagrangian as having arbitrarily-high order of spatial derivatives. That's why I know quantum mechanics cannot be non-local in any fundamental way, and the whole illusion must come from some kind of basic misunderstanding of the concepts. So it is you who's stalling any progress by repeating over and over some kind of half-diggested undestanding that is not correct and leads anyone who reads it --and believes what you say-- in the wrong direction. Your attitude, from a purely scientific POV, is obnoxious. At one point, it even reached that level from a civil POV, when you indulged in calling people names, when pressed for arguments you were unable to find.
  10. Yep. A big +1 to Hanke, as it was a very transparent account of the whole thing. Unfortunately, it's possible that this will not be the last word we hear from Bangstrom, and we get past Xmas still talking about it, to iNow's boredom and despair. We've got now 2 local experts, plus a bunch of other members, plus a panel of distinguished and reputable physicists, who've made their case against a standalone opinion. Can we call it a day?
  11. Sorry: I meant "The free non-relativistic Schrödiger equation," of course.
  12. The receiver instantly knows if it is “0” or “1” but they can’t know what it means because even the sender can't know what they sent. In other words. You're saying that somehow, what you say is true, just because you say so, but nobody can ascertain experimentally, or even in principle, that it's true. Your simulation of an explanation is more or less the same in all your posts: You somehow know you're right, but you can't quite put your finger on why it's right, or even what exactly it is that you're right about. At this point I'm only just curious about your convictions from a purely psychological point of view. There's certainly no science to be learnt from anything you say here. And again, quantum particles have no identity: https://en.wikipedia.org/wiki/Identical_particles#:~:text=In quantum mechanics%2C identical particles,one another%2C even in principle.
  13. The non-relativistic Schrödinger equation in thre dimensions is exactly solvable. It's not deceptive at all what happens in one direction, as it's completely separable. The propagator can be obtained exactly and shows equal dispersion --in empty space-- in every direction, as couldn't be otherwise, because it's completely symmetric under rotations. Because the Schrödinger equation is linear, it has no soliton solutions. You are right though in that other very different things are very different things than the thing I was talking about.
  14. I meant "coherence has been lost." Sorry! I do this again and again.
  15. Sorry, "break coherence." I mix up these opposites from time to time. Yes, I prefer Swansont's answer too. He's as brief as surgically precise. There are many instances in which you learn something about a quantum particle long before you do anything else with it. That's my understanding of filtering, for example. Measurement is not necessarily interaction. But some interaction is necessary at some point, of course, as Studiot just pointed out. Otherwise, as he said, how are you to tell anything about it? Sorry for not having addressed your specific concerns about entanglement. I've been talking about entanglement for like a month. I also have a feeling that some people see in entanglement something that's not involved in the principles of QM themselves, some new law, some extra magic. There isn't. All the mystery is already in the double-slit experiment already, or the "paradox" of partial reflection, etc. I also totally concur with MigL's comments:
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