Comments by "Lepi Doptera" (@lepidoptera9337) on "Cool Worlds" channel.

  1. Time is not a dimension. Time is that which the clocks show. The diagram basically relates clocks on Earth to clocks on Vega to clocks on the STL ship. The problem is that clocks order causal events by assigning time stamps to them. The only way you can have FTL is by allowing these time stamps to change almost randomly. So what is a causal event for one observer is not one for the other. If you make a movie out of this then you would actually see the frames in the opposite order, i.e. FTL could make it look like somebody on Earth could predict a supernova that hasn't happened, yet. Or predict next week's lottery numbers... which would make all kinds of games of luck completely irrelevant in an FTL universe.
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  2. There isn't. ;-)
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  3. How is the talking donkey thing better? :-)
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  4. The universe itself is sending you a signal from 300,000 years after the first second of the big bang. That signal can be detected with little more than a slightly larger tv antenna, despite the fact that it came form across 45 billion light years or so. The universe doesn't set any limits on communication within at least the local group of galaxies. If somebody wants to talk to you, they can.
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  5. That explanation is wrong. Particles don't even exist and quantum systems are in no state until measured.
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  6. No thing moves away faster than the speed of light. Things that leave the observable universe stop being things.
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  7. That was a load of bullshit.
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  8. No. In physics all information transfer necessarily requires a transfer of energy. The trivial explanation here is exactly the same as in case of perpetual motion. Energy conservation rules out any chance for perpetual motion. In this case relativity rules out any chance for either energy or information transfer.
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  9. There is no such thing as a collapse. That's just nonsensical language that keeps going around on the internet. Nobody in physics who knows anything of value about quantum theory uses that language.
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  10. What's up with the gibberish?
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  11. Relativity is not violated by this. It is, instead, relativity that prescribes the structure of quantum mechanics that makes sure that relativity is not violated. ;-)
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  12.  @benk79  Yes, that's because it is spot on. Quantum systems can not work any other way because they all live on a relativistic background. I don't know why this is not mentioned in textbooks. I never understood that part.
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  13.  @benk79  The EPR paper is nonsense. Three relativists can't tell that entanglement is a trivial consequence of relativity. That's a low point of theoretical physics, at most. It certainly isn't anything to get your panties in a bunch over. ;-)
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  14.  @benk79  I have contributed to the field of experimental physics, but even I can tell when a theorist misses a trivial consequence of his own theory. This question is so simple that it can be answered in an oral exam by an undergrad student. ;-)
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  15.  @benk79  Dude, it's not my problem that you wouldn't pass a second year oral exam. That's your problem. ;-)
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  16. It's both. It's an immediate consequence of relativity (and thus no worth thinking about any further) and it has been measured plenty in the lab (where it behaves exactly as the theory predicts... which means it's not worth thinking about any further because there is nothing new to be learned).
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  17. Measuring one quantum doesn't change the outcome of the measurement of the second. The measurement adds an uncertainty to the spin state that depends on the relative angle between the source and the measurement device but it does NOT set the spin state. That's a common misunderstanding.
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  18.  @Epiphone1964  Choosing the axis of measurement (polarizer or Stern-Gerlach) simply changes the uncertainty about the local spin state. If the axis is parallel to the spin state, then we get zero additional uncertainty. If it's orthogonal, then we get maximum additional uncertainty. The measurement is simply not angular momentum conserving if it's not parallel to the spin state. The additional angular momentum comes from the measurement system.
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  19. Yes, but his criticism was wrong. He simply didn't understand how quantum mechanics actually works.
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  20. There is no such thing as a collapse of the wave function. That's just a nonsensical term that you keep hearing on the internet. ;-)
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  21. Yes, that's what tachyons do. They step out... and as a result they are immediately gone. :-)
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  22. Or, you could pay better attention, instead. ;-)
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  23. Also completely wrong. ;-)
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  24. As soon as you observe a quantum computer the computation is over.
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  25. It does when you are on an FTL ship, but that's because the diagram is actually wrong for that case. The light cone gets narrower as we approach the speed of light and it contracts to the diagonal as we reach it. That's the famous "light does not experience time" case. However, if we evaluate it past that speed, then the cone doesn't start opening up, again, instead if flips 90 degrees out of the diagram. Time becomes imaginary. That's tachyons. Tachyons are not experiencing time because they are constantly decaying. There simply is no FTL coordinate system in which stable matter can exist.
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  26. There is no such thing as a collapse. There is an entangled quantum state with two potential quanta, one of which is the outcome of the measurement at A, the other is the outcome of the measurement at B. Whether we perform a measurement at A or not does absolutely nothing to the measurement at B. We can decide to perform that measurement of we can decide not to. The result of the other measurement will not be changed.
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  27. No, of course not. Many UFOs are simply cockpit canopy reflections. Others are meteorites or falling space debris. Even more are simply campfire stories. ;-)
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  28. We can control meteorite impacts. We have already proven experimentally that we can alter the trajectories of these bodies.
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  29. Quanta don't make "choices beforehand" any more than dice do.
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  30. The spins are determined by both, the initial emission of the entangled pair and the individual measurements. They do not exist before the measurements.
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  31. The speed of light is always the same for all observers.
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  32. Yes, the real thing is extremely simple. It follows trivially from special relativity. This is simply not the real thing. It's the physics equivalent of Trump being a stable genius. ;-)
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  33. Why are you telling us that you weren't paying any attention in school? How is that supposed to make us feel better around the holidays? ;-)
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  34. Most men and woman are falling very short on either count. ;-)
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  35. Superposition is a mathematical property of the theory. It's not a physical property of individual quanta and one can not "check superposition".
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  36. Nothing... except for the fact that "A quantum is a small amount of energy.". Energy can only be measured once.
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  37.  @rodm8113  What you call "collapse of the wave function" doesn't exist. What happens instead is that a measurement takes all of the energy out of the system. After the measurement the system is literally gone. It doesn't have any more energy to give. You want to measure an empty battery periodically? What does that give you? Always an empty battery.
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  38.  @rodm8113  No matter what A does, B always sees a random outcome. Same for B. What does a series of random outcomes mean? How are you extracting information from it?
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  39.  @rodm8113  Your previous response simply makes an incorrect assumption about the system. A measurement at A does not change B. Neither does a measurement at B change A.
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  40.  @rodm8113  Quantum computers can't beat relativity, either. If you can show me one article that says they can, then I will show you an article that's 100% wrong. :-)
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  41. No, you can't.
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  42. That sounds cool until you realize that you will have to branch the universe an infinite number of times because the causality violations happen differently for an infinite number of different observers. Just where is the energy coming from to create all those branch universes? :-)
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  43. Where does it probe? In the rear? ;-)
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  44. The universe does not have an FTL transmitter. It does everything at or slower than light speed. But since the universe has actual consequences, you can't avoid paradoxes. You need to pay more attention in school, kid. ;-)
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  45. @ Yes, you are correct about that. My attention span was just about enough to earn a PhD in physics, but I never even came close to mastering your job as a parking attendant. ;-)
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  46. Entanglement simply means that the physical vacuum does not change the total energy, momentum, angular momentum or charge of a multi-quantum system. And because it doesn't do that there is no information in it about anything. We knew at the beginning what those physical properties were and we still know at the end what they are.
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  47. Me reading Genesis won't make you smarter, I am afraid. :-)
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  48. It's not a theory. It's a trivial mistake. If you read Everett's thesis, then you can find it in the second sentence of that document. ;-)
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  49. Quantum entanglement is the equivalent of Newton's third law. It's simply momentum/angular momentum conservation. Conservation laws aren't effects at a distance. They are the absence of conservation law breaking mechanisms.
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  50. Stanislav Lem's last book is about just that. What do you do with an intelligence that doesn't want to talk to you?
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