Comments by "Lepi Doptera" (@lepidoptera9337) on "Sabine Hossenfelder" channel.

  1. You wouldn't exist without it. You are welcome.
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  2.  @filosofiadetalhista  Where am I attacking you? You are trivially wrong on a number of things and I am merely pointing that out. I would suggest that you leave your hurt ego at home. It has no use in science. There is no such thing as wave function collapse. A wave function is an abstract description of a quantum mechanical ensemble (i.e. a hypothetical infinite repetition of the same experiment). Just like a probability distribution a construction that depends on an average over an infinite number of hypothetical events isn't being changed by a single actual event. Copenhagen doesn't talk about collapse anywhere. It talks about the reversible dynamics of a completely isolated unitary ensemble of one system (as described by the Schroedinger equation) and the irreversible energy exchange between the first and an ADDITIONAL second system that performs "the measurement" (that's the function of the Born Rule). The entire "collapse" language is simply nonsense that you have picked up on the internet. It is, as far as I know, not even defined in textbooks. One system IS NOT EQUAL to two systems, hence there is a need for a second formula. Reversible dynamics IS NOT EQUAL to irreversible dynamics, hence there is, again, a need for a second formula. That's why the Born rule has to exist in one form or another. From a logical perspective all of this is crystal clear. What is not obvious is why our education system does such a poor job explaining these otherwise trivial facts almost 120 years after they were first properly identified. There is an incredible amount of confusion and very little clarity about the ontological connection between reality and the theory going on, both at the layman and the professional level. That confusion has to stop. With regards to your second point... the wave function approach does not lead to ultra-precise physics. It's a remnant of the initial non-relativistic phase of quantum mechanics. It explains some trivial systems (particle in a box, hydrogen atom) with reasonable precision and completely falls apart on pretty much everything else (it's almost useless on scattering problems like in high energy physics). One can not do quantum field theory with normalized wave functions and we don't. Reality IS NOT like the non-relativistic Schroedinger equation suggests. It just happens that the step up in mathematical difficulty between the non-relativistic case that has ontological problems and the relativistic field theory case that doesn't have them is enormous. It's far too much for most students to absorb. It also doesn't buy the practitioner anything to learn a theory that has very little predictive power at low energies where effective potential theories suffice and are much, much easier to use (like in solid state physics).
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  3. You need to start a church based on your beliefs. In the US religious income is tax exempt.
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  4.  @jonathanjollimore7156  Hmm... maybe less weed in the cookie will be better, next time?
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  5. Physicists don't measure the position of a photon because photons are irreversible energy transfers and energy doesn't have a position.
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  6. Great sarcasm. ;-)
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  7. ​ @OhAncientOne  Exactly. THAT is the the problem. ;-) Or, more precisely, the problem is to translate that question into an experiment or observation to which nature would give us a relevant answer. We don't have the means to perform such an experiment or observation. At least not yet.
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  8.  @kaushalsuvarna5156  It tells us absolutely nothing because light doesn't take classical paths. Classical paths are an approximation. Even in classical wave theory it's the replacement of (almost straight) wave fronts by their local geometric normals that we call rays. That's a good approximation for plane waves in the free wave propagation problem. It breaks down as soon as we have interaction with surfaces that are changing rapidly at the spatial scale of the wavelength. Then we have to use the full wave theory. In quantum mechanics the validity of these approximations breaks down even further because we are never looking at just one particular system. We are always looking at all possible physical variations of the system (that's called "the quantum mechanical ensemble"). The point I was trying to make is that there is a solid mathematical reason behind all of this "weirdness", but at the end of the day it all breaks down to having to give up the wrong mental models. The world is NOT made of material objects that are flying around on Newtonian trajectories. It is made of energy flow between systems. That energy flow obeys different rules than Newtonian objects (which don't exist except as approximations) would.
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  9. Your first sentence was already completely wrong and it got only worse from there. ;-)
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  10. Gravity is also not action at a distance. It travels at the speed of light.
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  11. I have never seen a physicist in full command of his mind who was tackling the consciousness problem. Neither have you.
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  12.  @eljcd  The initial calculation by Feynman? It is not naive. It's actually quite congenial and it works, with some difficulties. What is certain is that we haven't found anything better for over 70 years, which tells us that it's not all bad. Is it the best possible model for how quantum fields work? Certainly not. I am highly skeptical that the real/virtual particle picture is the best way to describe quantum fields myself. That, however, has absolutely nothing to do with the multiverse question. QFT tells us how to calculate with quantum fields and which kinds of quantum fields can exist, at all, but it does not tell us which kinds of quantum fields should actually exist. I am not aware that there were a whole lot of complaints about that in the past. If we were to put the same "prediction" criteria for the universe on plain QFT that we are putting on string theory, then we would have to conclude that it predicts an infinite number of possible universes. Instead we accept that it can't predict any. It can only describe the one we see. What happened with the introduction of string theory is that people had overblown hopes that it would reduce the number of possible quantum field theories to one. It didn't do that. It seemingly reduced it to a very, very large number. Unfortunately, so far nobody seems to have found the actual solution to the universe inside string theory, either. It may be in there, it may not be. And with that a serious philosophical mistake crept into the discussion: since string theory (which effectively has done nothing for physics proper so far) predicts a very large number of possible low energy universes, then maybe there have to be a large number of low energy universes. That is total nonsense, of course. The situation on the ground has simply not changed: we can describe the low energy universe very well, but we still can't predict it. We are still roughly where we were in the 1970s, when the SM was more or less finalized structurally. That is not a very long stretch of stagnation in physics. It was much worse in the 19th century when we had a more or less spotless (if inaccurate) theory of motion of matter without having any theory of matter, at all. So take the "discussion" with a grain of salt. It is far more about egos of different groups of people, neither of whom has a solution, than it is about the actual state of physics. Physics is just fine, it simply didn't make as much progress as some elderly physicist would like to have seen. Will Susskind be able to die in peace, having seen the holy land at least from afar? No. He can talk to Moses and Newton and Einstein about that experience when he gets to heaven. :-)
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  13.  @eljcd  I think there are a number of attempts to use more or less plain QFT to work around the gravity problem. There is the double copy group which says that basically two copies of the color force can produce gravity. I have yet to understand how that is supposed to work even even at the kindergarten level, so I can't comment. Then there is an attempt at making gravity a massive field, which could possibly explain dark energy, but the model seems to suffer from cosmological stability problems... quantum gravity seems a bit like playing Whack-a-mole, whenever a model is successful in one area, it has serious, if not deadly problems in another. My perspective as an experimentalist is a bit more focused on observations, right now. I don't believe that we will get the funding/develop technology to get beyond the 1TeV accelerator barrier within my remaining lifetime. So that leaves astronomical and cosmological observations. If you have been watching the success of gravitational wave astronomy and radio astronomy to image black holes, then it becomes somewhat evident that building new (space based?) observatories for gravitational, optical and radio-astronomy is the way to go. Nature has given us such a beautiful laboratory of absolutely monstrous extreme systems in the universe. We can never hope to replicate the conditions near and inside those objects in the lab, but we can harvest much of this information from a distance. That is where the near term progress of physics lies, IMHO.
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  14.  @augustinemmuogbana3382  The third party is nature. All you have to do is ask her. Let me know when she shows you a quantum fluctuation. I'll be the first one to congratulate you.
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  15. I like entropic gravity, too, but Verlinde doesn't seem to have made a whole lot of progress with the idea after the original publication. It's a cute bunny until one puts it under the microscope and then it seems to come with a lot of fleas that are not easy to get rid off, either. MOND and its different variations are not much better, of course. I would go with Einstein for now plus something else that we just don't know. That's the safe bet.
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  16. So was your mother's love. It still had consequences for your neediness. ;-)
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  17. So you know more about the universe than everybody else. Do you have a direct line to the gods? :-)
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  18. Musk is a hard atheist. His only religions are himself and money. ;-)
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  19. Bullshit. You never even went to university. :-)
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  20. First of all, none of this is for the unsuspecting masses. It's for professionals. Secondly, DCQE experiment are NOT meant to be time machines. They were meant to illuminate "reality" aspects of quantum mechanics. As such they basically just confirm what we have already known about QM since 1927: outcomes are NOT compatible with classical objects with classical state that are moving along classical paths. That some people were misrepresenting the facts about these experiments to make a quick buck with trolling on the internet and that the YouTube algorithm is helping them to do that is a problem YouTube has to deal with. It's not a problem of physics proper.
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  21. Technically the Nobel Prize doesn't work for physics, either. Nobel wanted it to be given for discoveries of value to the human race... and few relevant physics discoveries are falling in that category. Einstein didn't get it for the discovery of relativity, even though that is the centerpiece of physics. He got it for the explanation of the photoelectric effect, which is of enormous economic importance in form of solar energy (but they could not and did not know that back then)... but Einstein didn't discover it. He merely explained how it works.
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  22. Why don't you tell us your "theory"? :-)
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  23. None of this applies to physics because there are no sets in nature.
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  24. In ITER? Nothing. ITER will not solve that problem and it does not have that problem to begin with. It will never achieve continuous operation with neutron fluxes that will destroy the walls. It's still a confinement experiment. In practical reactors that function would be taken over by the breeding blanket, anyway, but so far nobody has solved that problem practically. I am not even sure anybody is working really seriously on it, yet.
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  25. How much do I have to drink to start seeing gravitons? :-)
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  26.  @BenIsInSweden  He is just full of it and only wants your attention. ;-)
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  27. You said it. IF we had been using math wrong. But we didn't. :-)
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  28. Physics is all about reality. We simply compartmentalize reality into smaller, easier to describe pieces. That's why we are the most successful intellectual discipline of all times. ;-)
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  29. ​ @moskitoh2651 My first theoretical physics teacher said this in the first few minutes of the first lecture: "Gentlemen. Physics is the art of approximation. Those of you who are not comfortable with the fact that physics uses increasingly more refined and accurate models of reality should leave this lecture now. The philosophy department is across campus. There you will learn the absolute truths about the universe... and they will all be completely false.". Big laughs, nobody got up to become a philosopher. You would, obviously, have been the exception. If you are looking for absolutes, that's philosophy and religion. Both are absolute bullshit. ;-)
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  30. Congrats. You are one in thousands who actually understands what is really going in.
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  31. Because a measurement is an irreversible energy transfer and an ideal beam splitter is reversible. A real beam splitter does absorb a little energy (because it has finite mass), but in practice that's very hard to measure and for most cases irrelevant.
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  32. Yes, that's complete bullshit. ;-)
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  33. Chances of DK effect are rising exponentially the further a person is straying from her area of expertise. Sabine Hossenfelder needs to be careful here.
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  34.  @anywallsocket  I thought we are talking about fundamental physics? The most fundamental physics we have right now is QFT. QFT tells you from first principles what can be measured "exactly" and it ain't much: scattering amplitudes. That's it. Everything else is an approximation based on semi-classical averages. Now, if you want to put philosophical bullshit on top of, that's fine with me. I will simply call it philosophical bullshit and move on.
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  35. Look, Ma! FUD at its finest. ;-)
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  36. Less alcohol will help. ;-)
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  37. Exactly. That's a good example for a free will algorithm that can not have a predetermined outcome that depends on our mind. Unless someone is a solipsist, of course. In that case the coin is just a figment of our imagination and it shows whatever side we have (unconsciously) chosen, already. Now we are in the deep end of human psyche, though.
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  38. We can imagine a lot, but reality will be much more mundane. Absolutely nothing interesting will show up.
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  39. You have been told correctly.
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  40. The least useful theory is the theory of everything. I don't know why people are so desperate for it. Most people are not even willing to learn the properties of the most trivial theories like Newtonian mechanics. What use would a ToE be for them????
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  41. Or... you could read von Neumann (1932). The solution is in chapter five or six, if I remember correctly and has been there for over 90 years, already. :-)
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  42. Bitcoin is a pretty trivial pump and dump.
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  43. Science is always looking for the unexpected. The problem in high energy physics is that most of what pops up these days is not. The last really unexpected finding were neutrino masses.
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  44. One can get around the idling by connecting the output of one LLM to the input of another. If you do that one of two things will happen: Either they reach a fixpoint or orbit or you will see the "conversation" descending into madness. ;-)
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  45.  @ggzibugg  Neoliberalism is not anti-science. Neoliberal business people know exactly that they can't operate without academics. What you are seeing here is not neoliberalism. It's not even fascism. The Nazis were absolutely enamored with science and technology. They just didn't like the fact that Jewish scientists were the leaders in their fields.
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  46. There is no such thing as a gravitational force to begin with and forces in quantum mechanics are not "fuzzy". The evolution of the quantum mechanical ensemble is completely smooth, even though special relativity forces the individual system to exchange energy, momentum, angular momentum and charges in discrete quantities, which in a certain semi-classical limit would make reality feel "shaky", but that's a problem with the special choice of that limit.
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  47. There is nothing interesting about MWI. Everett simply didn't understand what quantum mechanics is. He mistook the (admittedly misleading language) for gospel and created a piece of poetry in motion.
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  48. Because that's the "natural motion" in general relativity. With gravity the simple rectangular coordinate grid of your teenage years goes out the window and you have to learn some fairly heavy math called "differential geometry" to catch up with reality. Nature really didn't make this one easy for us. Not one bit.
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  49.  @keppela1  Physics is a description of observed reality. What we observe is that without gravitating bodies close by two objects are moving in a linear fashion relative to each other (as long as there are no forces acting between them). With a gravitating body they don't even do that. That's it. That's "all" physics has to describe. If that's not enough for you I can only offer you poetry, philosophy or religion as outlets. Science doesn't care about anything else but the description of the linear (without gravity) and non-linear (with gravity) motion. But since I am neither in the literature, philosophy or the theology departments I can't tell you what those other guys will be saying about the situation. Physics, OTOH, got its part all covered with Einstein's equations. ;-)
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  50.  @keppela1  Yes, you can look out the window and you will get a totally wrong impression about the world. Don't worry. That's pretty much what happened to everybody before physicists figured out how it really works. That's why we are the smartest of the smart, after all. :-)
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