Comments by "Lepi Doptera" (@lepidoptera9337) on "The Multiverse just Got Bigger: An Upgrade for the Many Worlds Interpretation" video.

  1. A measurement is an irreversible energy exchange. It does not have to be a macroscopic body that captures this energy. Even the loss of energy towards infinity (e.g. escaping electromagnetic radiation) is "a measurement". Technically that's the only measurement we need in quantum field theory (outgoing plane waves) but since we are impatient we usually put a thick piece of matter in the way of that outgoing radiation and we give it a fancy name like "detector". :-)
    2
  2. And there is the kid who wasn't paying any attention in high school when we told him that "photons are quanta of energy". There are no objects in quantum mechanics. ;-)
    1
  3. Except that the physical vacuum has the symmetry properties of nothing. ;-)
    1
  4. Physics is not mathematics. A meaningful function in physics has an interpretation in physical entities. Most people just don't understand what those are in the case of quantum mechanics.
    1
  5. There is no theory of cosmology. The official name is "concordance model" and it can be changed at any time as new data becomes available. What in the world are you talking about?
    1
  6. von Neumann was one of the best mathematicians who ever lived, but he could not understand the meaning of quantum mechanics at all.
    1
  7.  @ValidatingUsername  We have known how quantum mechanics works since 1927. We know how to derive it from first principles, too. All you need is Kolmogorov's axioms and a trivial application of Pythagoras. A congenial mathematician like von Neumann should have seen that in his sleep. And yet he didn't. ;-)
    1
  8.  @ValidatingUsername  They all thought that quanta are classical objects. That's not the case. Quanta are physical property exchanges. The second problem is that quantum mechanics follows from relativity and for the first 30 years it was treated entirely from the Galilean point of view. Feynman diagrams are still not properly understood by most people. They are a very nice theoretical tool but lead to an awfully flawed intuition in which space is filled to the brim with virtual particles. It's the other way around. Space is completely empty. It is completely empty at all times. That's what relativity tells us.
    1
  9.  @ValidatingUsername  Never. 99 of 100 physicists do, in my opinion, not understand what quantum mechanics is about. They don't have to. QM is a theory that is very suitable to a "shut up and calculate" approach. Even of you have wildly wrong ideas about what you are dealing with the math returns the correct answer. You can try it for yourself. Ask any physicist (other than me) how and more importantly why quantum mechanics can be derived algebraically from Kolmogorov. They won't be able to tell you. Most of them will probably think that you are trolling them. You will most certainly not make friends. ;-)
    1
  10. A measurement is an irreversible energy exchange. How much more precise do you need it? :-)
    1
  11.  @honaleri  You are correct. You aren't thinking. Hint: third law of thermodynamics. ;-)
    1
  12.  @honaleri  I have been thinking about this for the last 50 or 60 years, kid. Don't you dare feeling sorry for yourself, though. ;-)
    1
  13.  @honaleri  See, I told you not to feel sorry for yourself. You look even more silly now than in the beginning when it was just DK. Now it's DK and delayed emotional development. ;-) I told you all that there is to know about measurement in physics. That you didn't want to listen to this physics PhD is 100% on you, kiddo. ;-)
    1
  14.  @honaleri  Dude, I don't care about your emotional problems with authority. I told you the correct solution to your question: In physics a measurement is an irreversible energy transfer. It has to be an irreversible process because we demand it to leave a lasting record. It has to be a finite transfer of energy because of thermal noise due to the third law of thermodynamics. If we want the measurement to be reliable it has to be above the noise floor. :-) Yes, it is that easy. That you don't know something this trivial about physics completely disqualifies you in this field. That is all there is to it. :-)
    1
  15.  @honaleri  Sorry to inform you, but your entire first post was nonsense. I know where you got it from. It's called the "Heisenberg microscope" and it's Heisenberg's equivalent of Schroedinger's cat. If you read Heisenberg's original publications then you will see that the young Heisenberg had an incredible intuition for the ontological questions. Initially he got things right but then he aged and he developed a "philosophy of physics" and that's when he got it all wrong. His later writings are total garbage. The simple fact is that particles don't exist. Quantum mechanics is not about objects. It's about energy, momentum, angular momentum and charge exchange between system. If you know that and you also know that individual quantum detections are statistically independent, then you can derive all of quantum mechanics from Kolmogorov's axioms in a few pages of high school level algebra. There is absolutely no need for guesswork here. The founders had to guess a lot of things, but today we know how to derive all of this systematically. We do not teach this properly, though. Not even at the university level. If you want to get a really good understanding, then you will have to dig through the primary literature yourself. It's all there in the physics library. Peace!
    1
  16. Physics is not about calculations. It's about the description of complex phenomena of nature using simple phenomena of nature.
    1
  17. Yes, all of that was bullshit. ;-)
    1
  18. Quantum mechanics can be derived formally from Kolmogorov (with a sprinkle of relativity) in a few pages of high school level math. Congrats, you just won the Dunning-Kruger Award for Excellence in Intellectual Laziness and Hubris. ;-)
    1
  19. What have you been smoking? ;-)
    1
  20. It's not a feature but a mistake. Everett did not understand that quantum mechanics is an ensemble theory and he assigned the wave function to single quantum systems. It's like the assumption that every dice roll can already predict what the outcome of the next roll will be. It's just total nonsense.
    1
  21.  @neuroatrok  A single atom is a single quantum system. When it decays from its excited state into its ground state it gives us one photon of energy. After that it can't give us anything anymore. There is no more energy in there. When we measure one photon, we can get the following information: energy, momentum and angular momentum. That's it. There is no more information in that one event. In contrast the wave function of the electromagnetic field contains an infinite amount of information about the field. That's because the field can only be measured (precisely) by taking the average of an infinite number of photon detections.
    1
  22.  @neuroatrok  Pretty much. The language in Everett's thesis is not even his own. He most likely got it from von Neumann's book or some other authors who wrote it that way. In essence these things are outcrops of really horrible language use in modern physics that implies mental models that are inaccurate and completely misleading. We know today that the structure of quantum theory can be derived from the same axioms (named after Kolmogorov) that mathematicians use to define probability theory. What this implies is not even that we are talking about probabilities. It only requires that individual experiments (like the emission of light by individual atoms or the decays of individual nuclei) are independent (i.e. that there is no causal relationship between any two events). This leads to seemingly "random" time series, but that's entirely irrelevant for the theory which only predicts averages. The deeper reason for the independence is relativity, i.e. it is a physical reason that lies outside of the structure of the theory to begin with. It is therefor completely pointless to look for some unknown internal ("hidden") variables that we have not been able to identify, yet, or for some magical mechanism that restores "classical" deterministic behavior. That is simply not how a relativistic universe behaves.
    1
  23. The math of quantum mechanics agrees with every single observation we have ever made. ;-)
    1
  24.  @zelfjizef454  She doesn't understand what the math does. Plain and simple. You are simply looking at a case of Dunning Kruger. ;-) The math behind quantum mechanics comes from two sources: Kolmogorov's axioms for independent choices from a sample set and relativity. Independence can be tested statistically and relativity has never been observed to be violated. I doubt Sabine understands this.
    1