Comments by "Lepi Doptera" (@lepidoptera9337) on "My problem with the black hole information loss problem" video.

This has nothing to do with publishing. These kinds of problems are always theoretical. The formulas that a theorist can derive about them CAN NOT be solved in practice. They have no predictive power in experimental terms. They are entirely formal in nature. So now you have to ask yourself if you really want to "silence" mankind about completely formal solutions to in practice unsolvable equations. What good does that do, actually? Isn't it more about your ego that feels threatened because a smart person can do something that you can't, no matter how "useless"?
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The assertions here aren't flawed. They are exactly the same as for all other systems. Hawking radiation, for instance, is nothing else than the third law of thermodynamics applied to a strongly gravitating system. A black hole, no matter how massive, has to have a temperature. Bekenstein, Hawking and others have simply answered the question what that temperature ought to be (and relevant surrounding questions on top).
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Great sarcasm. ;-)
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@AlgeistNydream The original was Galileo's ship. Einstein just modified it a bit for the case of gravity. It's amazing that Galileo basically had all of physics in his hands (or mind) in 1630... it was the ultimate divine revelation in all of physics. He just didn't know it.
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This is more about finding ways of describing unitary dynamics of black holes than anything else. That all "real" physical systems are losing information (energy, momentum, angular momentum and charge) towards infinity is well known. That's just thermodynamics at work. It does not change if we replace classical mechanics with quantum mechanics. We just end up with infinitely larger phase space (which many theorists ignore conveniently) but the basic upshot is the same: systems radiate and that radiation contains "the information loss". Take an ice cube. Leave it on the table for a couple of hours. It exchanges heat with the environment (that's the information loss mechanism) and what's left is a puddle. The shape of the puddle tells us nothing about the shape of the original ice cube. What theorists are trying to do here is basically just that: extract information about the black hole from the distribution of its Hawking radiation. In practice impossible. In theory, however, there is a formula (that one simply can not solve) that should be doing just that. There are actually two of these: the classical one that has one Hamiltonian phase space and a quantum mechanical one that has an infinite number of copies of that phase space in it. The two differ in their results. Surprise. Quantum mechanics IS NOT classical mechanics. Or better... it's STILL NOT the same, not even with gravity in the mix.
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@NicholasLatipi The underlying theory can be tested just fine. There is no requirement in science that every prediction of a theory has to be testable. Classical mechanics predicts the Poincare recurrence theorem. It's untestable. Does that invalidate classical mechanics as the right tool to fly to Mars with?
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@NicholasLatipi Nobody is trying to test a theory of quantum gravity here. We are simply asking the question which properties ALL viable theories of quantum gravity have to have in common. You can compare that to the Planck radiation phase of quantum mechanics. People had no clue in 1900 that they would eventually end up with U(1)xSU(2)xSU(3), but the Planck curve is still perfectly valid.
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@NicholasLatipi Youi can't know if something testable will jump out of the equations until you solve them. I am not sure what you are suggesting here? Arbitrary barriers what scientists are and are not allowed to think about? I am completely agreeing with you that the likelihood of testability remains low for ALL versions of quantum gravity. There might be tabletop experiments that can identify individual gravitons similar to how the Millikan experiment identified individual electrons... but Millikan didn't tell us anything about the electron-proton scattering cross section at 17.9GeV... so there. Testability is NOT the end of all means. It's just a tiny fraction of what physicists do. Beyond testability we are still required to think about both high level structural question of models and theories AND we need much more detailed experiments that go beyond yes/no answers. As critical as I am about this kind of "not even false" work myself, it has to be done by someone.
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Science is funded exclusively by tax money. What does that have to do with quantum gravity research?????
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@michaelkaliski7651 No, optical photons do not, but photons at high energies do. That's because the electromagnetic field has coupling terms to all other charged quantum fields (like electrons, muons, quarks etc.). The perturbation theoretical model of a photon-photon process requires a virtual pair of one of those other fields in the intermediate state. That's math, of course. In reality the physical vacuum is "non-linear". It's just not directly non-linear but it has a large number of constituents that couple in a bi-linear fashion. The bi-linearity leads to an EFFECTIVE or EMERGENT non-linearity. Yes, nature is complicated. If it weren't, then we would not be here. There would, at most, be a free photon gas. How boring.
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Classical physics is not time reversible. Proof? A global lubricant market with an annual revenue of over $100 billion. Only the most trivial examples of classical systems are time reversible, but one can also give absolutely trivial examples of dynamically irreversible classical systems. A ball rolling down a hill (inclined plane), for instance. Almost all n-body systems in Newtonian gravity are irreversible. In practice this is actually important because it predicts the instability of planetary systems, globular clusters, galaxies etc..
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@peterweston1356 That is what Sabine makes her money with: your ignorance of high school physics. ;-)
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@peterweston1356 Only the best fake news for you, my friend. Only the best. :-)
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