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Everything posted by joigus

  1. Oh, I see. You mean the infamous narcissist heckler of Witten that says all of modern physics since Planck is nonsense: https://youtu.be/k7EnQd-VGqU?t=27 I know what you're up to now.
  2. I'm not sure that's tenable, or necessarily true, or at least plausible. It could be. At present in QFT "virtual particles" is nothing but a fancy name for quantum mechanical amplitudes that cannot be made consistent with the on-shell condition, but must be included in the calculations. Nobody has seen a virtual particle, and I'm sure nobody will. In that sense, they might perhaps be comparable to the interior of a BH. Is it really there? I don't know, and I can't even think of a way to measure what's in there and report to the experimental physicists outside. You could say "I think ordinary space is made up of swarms of black holes that appear and disappear so rapidly that the deviation of their effect is immeasurably small." Similarly, I can't even conceive of a way to have a virtual particle do it's "virtual particle job" --participating in the amplitude off-shell-- and be possible to measure. You can perhaps always modulate a discontinuous pattern of behaviour by using an ad hoc sigmoid curve that does the trick. But remember virtual particles come in all kinds of flavours, masses, and other quantum numbers. So the concept is not to do with gauge bosons per se.
  3. And I have absolutely no objection to any of your explanations, of course. It's just that, within the context of the OP question, @exchemist posed a very interesting --very much related-- meta-question about virtual particles perhaps being responsible for what we perceive as the force between charged particles and their currents. It's because of its interest, and there not being any direct derivation --that I know of-- from QED that gives you the law of force between macroscopic charges or currents, that I sketched that kind of argument. It's not completely general, of course. Also, charges in currents are already moving. But if they're moving at constant speed, there would be no reason --from a classical POV-- why they should radiate. Only accelerating particles should radiate. I'm sure the relativistic argument I presented here can be extended to particles moving at constant relative speed. You need some kind of mechanism that's equivalent to virtual particles at some point. The gist of it is: If you assume charged particles to start moving because of the exchange of a particle, it's impossible to assign an energy and momentum to this carrier of the interaction that's consistent with special relativity. Therefore, there must be so-called off-shell particles. That is, particles that violate Einstein's relation. Those are virtual particles.
  4. That's a very interesting question I don't have a totally rigorous answer to. You are totally correct in making that distinction. So-called real photons are indeed those that can be detected with, eg, a photodetector. In some sense they're "somewhere there." Virtual photons, OTOH, are only those that appear in QED calculations as taking part in intermediate states that only are relevant to the effect of calculating the initial and final states of real particles, including other photons, or the vacuum. If you're familiar with Feynman diagrams, think of the external legs of the diagram as real particles. In between legs you have internal lines connecting vertices. These vertices represent local interactions via virtual particles that mediate the interaction, like in this image taken from Wikipedia representing electron-electron scattering: Now, this is all very interesting, but what happens when a big chunck of magnet attracts/repels another magnet? And when two charged pieces of matter do a similar thing? Can we extrapolate that picture somehow? I'm not aware that anybody has taken QED to do the detailed calculations on, say, a big piece of ferromagnetic material. But here's one reasoning that I think is very convincing to see why it has to be the case that it's virtual particles that are doing the job. One of the characteristics of virtual particles that we learn from QED is that they violate Einstein's energy-momentum constraint. They can do so because they're only allowed to exist for a very ephemeral time lapse consistent with HUP. The way to see that is that a particle at rest cannot emit a photon and start moving from the recoil. This is a very surprising consequence of special relativity. And here's the proof. A massive particle has 4-momentum that we can write as, \[ \left(E,c\boldsymbol{p}\right) \] satisfying Einstein's constraint, \[ \left(mc^{2},\boldsymbol{0}\right) \] Thin, of a charged massive piece of matter that's sitting somewhere, and consider the rest frame. We have a 4-momentum, \[ \left(mc^{2},\boldsymbol{0}\right) \] And now it emits a photon. We have --by virtue of energy-momentum conservation, \[ \left(mc^{2},\boldsymbol{0}\right)=\left(E,c\boldsymbol{p}\right)+\left(\hbar\omega,c\hbar\boldsymbol{k}\right) \] But the total 4-momentum is the very same 4-vector it was before, in particular it must satisfy the same Einstein relation, so that, \[ \left(E+\hbar\omega\right)^{2}-c^{2}\left(\boldsymbol{p}+\hbar\boldsymbol{k}\right)^{2}=m^{2}c^{4} \] The corresponding pieces must satisfy their respective Einstein relations, because someone seeing a piece of matter out there doesn't know it has just spat out a photon. Let's suppose the same goes for the photon. So, \[ \left(E+\hbar\omega\right)^{2}-c^{2}\left(\boldsymbol{p}+\hbar\boldsymbol{k}\right)^{2}=m^{2}c^{4} \] \[ \overset{m^{2}c^{4}}{\overbrace{E^{2}-c^{2}\boldsymbol{p}^{2}}}+\overset{0}{\overbrace{\hbar^{2}\omega^{2}-c^{2}\hbar^{2}\boldsymbol{k}^{2}}}+2\hbar E\omega-2c^{2}\hbar\boldsymbol{p}\cdot\boldsymbol{k}=m^{2}c^{4} \] so that, \[ 2\hbar E\omega-2c^{2}\hbar\boldsymbol{p}\cdot\boldsymbol{k}=0 \] and inevitably, \[ E\omega=-\hbar c^{2}\left|\boldsymbol{k}\right|^{2} \] which is impossible if both energies are positive. So photons emitted by a particle at rest seem to be an impossibility unless we admit the possibility that the electromagnetic field carries with it allowance for these ephemeral modes of propagation. As soon as the charged particle starts accelerating, then --I assume-- both real and virtual photons are being exchanged. The detailed picture being far more complicated than this. I forgot to say. The last step is on account that, \[ \boldsymbol{p}+\hbar\boldsymbol{k}=\boldsymbol{0} \] due to 3-momentum conservation.
  5. \[ \overset{m^{2}c^{4}}{\overbrace{E^{2}-c^{2}\boldsymbol{p}^{2}}}+\overset{0}{\overbrace{\hbar^{2}\omega^{2}-c^{2}\hbar^{2}\boldsymbol{k}^{2}}}+2\hbar E\omega-2c^{2}\hbar\boldsymbol{p}\cdot\boldsymbol{k}=m^{2}c^{4} \] OK then.
  6. Just been trying to remember something I'd read long ago about episodic memory that could be relevant to this discussion. https://www.psychologicalscience.org/uncategorized/myth-eyewitness-testimony-is-the-best-kind-of-evidence.html https://www.psychologicalscience.org/news/mandela-effect-what-is-it-and-why-does-it-happen.html https://www.researchgate.net/publication/256375079_Collective_representation_elicit_widespread_individual_false_memories https://en.wikipedia.org/wiki/False_memory#Mandela_effect (My emphasis.) While I have the greatest respect for the Law, and I always abide by it and recommend everybody to do the same, we should always keep in mind that in the end it is a product of human convention, while science ellucidates facts and correlations between those facts. If science makes it objectively, reproducibly, and unambiguously clear that we have reasons to believe witness accounts are not totally reliable, the Law --and the law people-- would be well advised to take science's salient facts into account as, in the words of a famous scientist, "Nature cannot be fooled."
  7. Nay, it is thou who discombobulates me with thy maelstrom in a way.
  8. No, it's not. No, I'm not. This has taken me back to when I was aged seven, and having arguments with my classmates. Not very long after the paper you're trying to get credit for was published. Thanks for the memories.
  9. Let me clarify further: It's not a new elastic action, is it? It seems to be good-old Sakharov's action in a bizarre notation. So what appears to be 'new' is how cavalierly you deal with divergent integrals by substituting them for a number and then using some numerical analysis by means of a handwaving 'technique.' It's actually your method for regularising the integrals that's to be subject to scrutiny. Experts are likely to ask you about that. Can you justify the only thing that's new, please?
  10. Thank you. Feel free to add anything I may have missed.
  11. joigus


    Adding to what @studiot said, you can study the molecular structure of something by turning it into a crystal, and study the diffraction pattern. That's not exactly heating it. It's how Rosalind Franklin obtained the spatial patterns of DNA that helped Watson and Crick understand its structure. I hope we're converging to a satisfactory explanation here, but some feedback would be nice. I hope that helps.
  12. joigus


    Tipically you first make them gases. Solids have continuous spectrum. Gases have discrete lines of emission and absorption. These lines are kind of the ID of different elements and chemicals.
  13. Photons do not cause magnetic attraction. First, the classical EM field consists of very rapidly oscillating electric field, and an associated --also very rapidly oscilating-- magnetic field perpendicular to the E field, and both perpendicular to the direction of propagation of such EM field. Particles are predicted to oscillate in response by the theory, and so it is confirmed experimentally. That's how antennae work. It's oscillation, rather than overall attraction. Photons, OTOH, are quanta of such EM field. They can be absorbed, emitted, scatter... They never result in overall attraction either. They just change the state of electrically charged particles by making them change their energy and momentum. I hope that helps.
  14. It seems there have been other people working on the very same thing. Why don't you quote other people's work on exactly the same? Sorry I said, I should have said, "the action --which is nothing but the Lagrangian integrated over time." The Lagrangian density integrated over space gives the Lagrangian. Anyway, you seem to be using a very peculiar renormalisation scheme. You just plug in some constants and do some dimensional analysis from there. What renormalisation technique are you using?
  15. Just a few preliminary questions. If it's all about Sakharov's Lagrangian from 1968, the action --which is nothing but the Lagrangian density integrated to all of space--, must lead to exactly Sakharov's action from 1968. So, In what sense is it new? In what sense is it elastic? Why no mention of current work on Sakharov's Lagrangian? --as late as 2018, from what I gather. Why do you not consider Planck's length as a reasonable cutoff, and concentrate only on EM, though make comments on QCD, which has a completely different coupling constant? About notation: What does it mean when you write bold-face symbols? That's usually reserved for vectors or tensors, not for scalars? In what sense are you singling out these scalars? And last but not least, What are your conclusions?
  16. And not a tale. Moby Dick could've ended up with Ahab having Moby for dinner, or the other way. Cantor's diagonal theorem has only one possible ending: Its logical conclusion. Spoiler alert:
  17. @Markus Hanke is absolutely right. When one talks about something being symmetric or not, one must specify what is symmetric --the object-- with respect to what --change of POV, transformation, etc. What Markus has shown to you is that, assuming two observers assign respectively coordinates \( \left(t,x,y,z\right) \) and \( \left(t',x',y',z'\right) \), the metric --given by \( t^{2}-x^{2}-y^{2}-z^{2} \) doesn't change --it's the same in the primed coordinates and the unprimed ones. It might be that what you mean is that the law that user with primed coordinates uses to correlate his observations with those of user with unprimed coordinates is not the same with \( \boldsymbol{v} \) replaced by \( -\boldsymbol{v} \). But it is. Both relative velocities are obviously collinear, so, \[ x'=\frac{x-vt}{\sqrt{1-v^{2}/c^{2}}} \] \[ ct'=\frac{ct-vx/c}{\sqrt{1-v^{2}/c^{2}}} \] \[ y'=y \] \[ z'=z \] (simple Lorentz transformations in one direction, AKA 'boosts') Introducing the definitions, \[ \gamma=\frac{1}{\sqrt{1-\beta^{2}}} \] \[ \beta=v \] The reciprocal ones obviously are, \[ \gamma'=\gamma \] \[ \beta'=-\beta \] and you get, \[ \left(\begin{array}{cccc} \gamma & -\beta\gamma & 0 & 0\\ -\beta\gamma & \gamma & 0 & 0\\ 0 & 0 & 1 & 0\\ 0 & 0 & 0 & 1 \end{array}\right)\left(\begin{array}{cccc} \gamma & \beta\gamma & 0 & 0\\ \beta\gamma & \gamma & 0 & 0\\ 0 & 0 & 1 & 0\\ 0 & 0 & 0 & 1 \end{array}\right)=\left(\begin{array}{cccc} \gamma^{2}\left(1-\beta^{2}\right) & \beta\gamma-\beta\gamma & 0 & 0\\ \beta\gamma-\beta\gamma & \gamma^{2}\left(1-\beta^{2}\right) & 0 & 0\\ 0 & 0 & 1 & 0\\ 0 & 0 & 0 & 1 \end{array}\right)= \] \[ =\left(\begin{array}{cccc} 1 & 0 & 0 & 0\\ 0 & 1 & 0 & 0\\ 0 & 0 & 1 & 0\\ 0 & 0 & 0 & 1 \end{array}\right) \] which more compactly reads, \[ \Lambda\left(-\boldsymbol{v}\right)=\Lambda^{-1}\left(\boldsymbol{v}\right) \] In what other sense you might want it to be more symmetrical, I don't know.
  18. The question is extraordinarily complex. Some people are OK with organised religion, but would cross the street when they see a lone 'nutter' preaching. Other (religious) people see both (any) other religion and atheism as a ticket for eternal damnation. Still other people are extremely intolerant of anybody who understands life in a different way, let alone if they have a different belief system, so not primarily having to do with religion... Some of these factors can be intesified by a genetic condition, or because of the way the person has been raised... Or in spite of the way the person has been raised. Educational strategies backfire sometimes. Extreme stress, a really hot day or a room packed with people can lower your tolerance level considerably. From what I know of cognitive science, the experts are continually trying to trace correlations between subtle --and not so subtle-- effects such as these. So complexity, complexity, complexity. The best bet is to try to elucidate correlations, I suppose. --Funny. I've just posted this and I get an ad from a chiromancy service. Coincidence or cookie-incidence? LOL
  19. I think this pigeon is a zilchist. Ok, sorry I missed the phobic nuance. I think phobias can have both a nature and a nurture component to them too. I'm not 100 % sure about it, but AFAIK many behavioural traits do.
  20. We might agree on more than you think, if we clarify our respective definitions. Following literally in your defining footsteps, pigeons --or some kind of Kaspar Hauser, for the purpose of making it a person-- are/were/would be atheists. They don't believe in god, even though they're clueless about it. But we need a definition. In a wider sense, I would say there must be both nature and nurture factors in determining how gullible a person is. I very much agree with, But I also think, eg, that a person with StPD would be far more likely to believe in all kind of supernatural things than a person whithout such condition.
  21. LOL. I suppose it's very much about how much stock you put in it. I could become a bigendian --or a zilchist-- in a matter of seconds if my life depended on it.
  22. The way I see it, you certainly need a certain amount of exposure to the concept in order to be able to tell whether you believe in it or not. Suppose you arrive on a planet where a furious debate is going on about the concept of 'zilch.' The first thing they tell you upon your arrival is: 'Hang on, are you a zilchist or an azilchist'?
  23. Depends on what you mean by an 'atheist'? Are pigeons atheists? They certainly aren't religious. I'm guessing when we say 'I'm an atheist' we're refering to some kind of criterion based on a previous framework of ideas.
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