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Showing content with the highest reputation on 10/07/22 in all areas

  1. No it’s not. It’s the simplest possible wave equation for a relativistic scalar field without spin. There’s nothing controversial about it. It’s not an arbitrary assumption - the Klein-Gordon equation is simply the Euler-Lagrange equation corresponding to the simplest possible Lagrangian for a scalar field. Of course - that’s because the equation is Lorentz invariant, so space and time need to be treated on equal footing. This follows directly from the Lagrangian.
    3 points
  2. Once you've removed it properly, it should be soaked in a mixture of salt water and ammonium alum. From there, it really depends on what you're going to do with it. If you're just covering your copy of the Necronomicon, you don't need it to be as supple as you do if you plan on wearing it again.
    2 points
  3. Well, a magnetic field is a particular aspect of the more general electromagnetic field - simply speaking, its defining characteristic is that magnetic field lines do not end anywhere, ie they either form closed loops or extend to infinity. In contrast, the field lines of the electric field begin or end at electric charges, but never form closed loops. Both the electric and the magnetic field are aspects of the same underlying entity, which is the electromagnetic field. All observers agree on what the EM field is, but they each see a different mix of electric and magnetic fields, depending on their state of motion with respect to the sources (electric charges).
    2 points
  4. Despite the lack of feasibility of cooling whole lakes, algae bloom are also driven by nutrient influx (e.g. agriculture). Cooling the system down would slow it down a bit, but it seems like trying to address the wrong issue with a lot of effort.
    1 point
  5. Oh, boy. This is SOOOO exciting. For some reason I'm not allowed to react to your post. I'm not cajoling you, honest. I'm just thankful that you're here. I think @bangstrom is half-way there. Swansont has been there all the time, because he takes no bullshit. Let me just repeat your points (echoing Zeilinger): Just one observation: What about a combination of some of them? Eg, it could be: 1yes, 2no, 3no, 4no, 5no. (yes-denying/accepting, no-denying/accepting; that's my take.) Careful everybody, because some are "deny" and others are "accept." The logical tree becomes more complicated when you consider more and more possibilities. 3 is important, but obscure. That's what I think is the case. I think it's a "no." And I also think there's experimental case for it. I'd be very interesting to learn about Zeilinger's take on it. 5no because 5no <= 2yes We're getting there, we're getting there... It's such a pleasure to have you here, @Eise. We may have to agree on terms of what 3 actually means.
    1 point
  6. With a single particle, entanglement of course plays no role at all. Which is what Zeilinger says: But Zeilinger uses it in his argumentation for his view. Look how he is doing it: Zeilinger discusses 5 ways out after the confirmation that QM violates the Bell inequalities. Deny realism Deny locality Deny counterfactual definiteness Accept superdeterminism Accept actions to the past He more or less discards 3 4, and 5 rather briskly. Of locality, as already cited early, he remarks that most physicists think that we should give up on locality. However he tends to give up on realism, because this seems to be the conclusion of the Kochen-Specker theorem, and its first empirical tests. So the KS theorem has directly nothing to do with Bell states. But for Zeilinger it is a hint that of 'local realism' (which, as Joigus explained means 'locality' and 'realism' taken together), we have to loosen our concept of a reality behind our quantum measurements. Please reread the chapter 'What could that mean?'. (Warning: he does not discuss these in the exact order as I did here. I streamlined his argument here. First he mentions the first three assumptions, then he argues against (3), then he discusses locality and realism, and only then he mentions superdeterminism, retro-temporal causation, just to discard them immediately.) @joigus: as you see, Zeilinger argues against superdeterminism. He treats it as a kind of 'last straw'. This is his argument: For completeness the 5th:
    1 point
  7. For a recent work on knotted topologic solutions of Maxwell equations: https://arxiv.org/pdf/1502.01382.pdf The biblio will take you back to the origins of this extensive body of work. My --recently deceased-- and dearest professor Antonio Fernández Rañada* was one of the pioneers, along with José L. Trueba. Both of them I knew personally, and I can attest to the fact that they have done very interesting work in the field. * I will never forget Rañada. I got my paper on quantum theory of measurement peer-review-published thanks to him, in the face of staunch opposition of other members of the Faculty.
    1 point
  8. You should do it in safe mode.. https://www.google.com/search?q=restore+in+safe+mode Especially if safe mode is problem free..
    1 point
  9. Not posting spam bait, and not posting in the wrong section of the forums, helps tremendously. We are awaiting the inevitable followups with "helpful" information.
    1 point
  10. Simply buy 120 GB SSD drive in any neighbor computer shop for $15 and install fresh OS.. If it is not hardware issue it will help straight away.. Then you will be able to copy precious files from old drive. e.g. 13.59 usd on eBay https://www.ebay.com/b/120GB-Solid-State-Drives/175669/bn_56798086 Everybody should have emergency drive in emergency situations to be able to install fresh OS on it, and boot. And bootable pendrive with Live Linux e.g. Kali Live: https://www.kali.org/get-kali/ Any pendrive 4 GB+ will be good. Only 4GB on it will be used for data. But first, boot in safe mode, and check if it works good or not! https://www.google.com/search?q=how+to+safe+mode+windows+10
    1 point
  11. Hi. Try deleting items in the recycle bin that qualify. Delete temporary files. Shut off WiFi and plug the ethernet to evaluate difference. Check all the installed RAM memory reports complete. Check available unused space in the hard drive.
    1 point
  12. Not so fast. He says "abandon local realism." Abandoning faithful Stalinism does not imply abandoning faithfulness, does it? NOT (A AND B) = NOT(A) OR NOT(B) As quantum mechanics abandons realism from the start, abandoning locality is not necessary. In fact, it would be quite silly to do so. The Kochen-Specker theorem is more ontological. It does not say anything about locality. It goes to the heart of the matter, which is indeterminism, of course. The background of it is V. Neumann's theorem. Gleason's theorem is, so to speak, a basic version of it. But these theorems were proven insufficient by John Bell, who also contributed to the theorem, providing a proof. When the dimension of the Hilbert space is at least 3, you can build observables that cannot even be represented consistently by hidden variables, so to speak. Here's a sketch of the argument: https://plato.stanford.edu/entries/kochen-specker/ There's a much more complete account of it in, Incompleteness, Non-locality, and Realism, by Michael Redhead. But it's dealt with by means of the heavy machinery of spectral analysis. It's been a long time since I spent any time reading or thinking about the "ontological" versions of the impossibility theorems for hidden variables. I don't think there's any interesting physics behind them, TBH. Producing noiseless quantum signals, that's another matter. That opens up wonderful technological possibilites. But Star Trek? Forget about it!
    1 point
  13. Try running OS in safe mode. https://www.google.com/search?q=safe+mode+windows+10 Does it help? Try restore system from restore point: https://www.google.com/search?q=system+restore+windows+10 ..it might be buggy gfx driver.. try downgrading..
    1 point
  14. Oh you Brits and your gin. When your neighbours make perfectly acceptable scotch ...
    1 point
  15. I stopped watching basketball because of Shaq and his stance that he didn't want to be a role model to children. I'm grateful for the extra time this gave me to study science, and I'd be equally grateful to know that children no longer look up to him. And I'd tell him that to the top of his chest, being 6' 3". But it makes sense that Shaq is a flat-Earther. Most of those folks are droolers, so a dribbler will fit right in.
    1 point
  16. Elementary particles don’t have an internal structure, because they are local excitations of quantum fields. Such fields don’t have structures. In tech speak, elementary particles are irreducible representations of symmetry groups. There is no physical principle requiring all particles to have internal structure. E=mc^2 has nothing to do with potential energy, which is what you must be referring to in this statement, or else it doesn’t make sense. It’s the energy equivalent of the particle’s rest mass, and this relationship is true only in a massive particle’s rest frame. This has nothing to do with any potentials or internal structures. E=mc^2 has nothing to do with potential energy, nor internal structure. Only with rest mass. No, see above. No, I am saying that there is no internal structure, according to current understanding of the Standard Model. Elementary particles are irreducible - and that’s true for all of them, irrespective of whether they carry electric charge, colour charge, flavour, isospin, or mass. To experimentally verify the elementary-ness of such particles, you use a technique called deep inelastic scattering. This is, however, limited by the available energy of the accelerator. Proposing internal structure for these particles means you need to introduce new physics.
    1 point
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