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Eise

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Eise last won the day on October 28

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    University degree philosophy, subsidary subject physics
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  1. And I explained that nobody was even saying this. So you were beating a dead horse. So let's try to explain it once again. As a starting point we take a Bell experiment, that closes the communication loophole. This means: the measurements cannot influence each other with a light signal, or any slower signal the decision which spin direction will be measured is taken after the particles left the entanglement source So there can't be any causal connection between measurement device A, B, and the entanglement source. Said otherwise, no communication is possible between these 3 components. To make the example as simple as possible we also assume that detectors and entanglement source do not move relative to each other, and the entanglement source is exactly in the middle, so the measurements are exactly at the same time in the rest frame of the experiment. Are you with me so far? Maybe Joigus' drawing helps: Just take Alice and Bob as other names for the detectors. So now we ask ourselves what Carla and Daniel will see. Well, it is in the drawing: in Carla's frame of reference the measurement at Bob's side is first, for Daniel's FoR it was Alice's side. It is just a question of perspective, not of changing anything with the experiment of course. Got that too? Now according SR observers can disagree on the timely order of events, when these events are space-like separated. But that is exactly what the closing of the communication loophole means. But SR also states that Carla and Daniel should at least agree on the physical process. But they don't: according to Carla, Bob's measurement determined the outcome of Alice's according to Daniel, Alice's measurement determined the outcome of Bob's But these cannot both be true. So the conclusion is that there is no 'determination relation' between the measurements. So no signal, FTL or not. For Alice and Bob of course nothing changes. In their FoR the measurements are simultaneous, just as before. So Carla or Daniel have no influence at all on the experiment. But they should agree at least on the physics.
  2. Seems you have wax in your ears: Nobody claims that observers that are in other inertial frames of reference affect the experiment. There you are right, for one time. To understand entanglement, one must understand QM. But as said, SR is a 'filter' for possible explanations. If an explanation is in conflict with SR, then it is wrong. Yes, that is what I said. (No, it wasn't, but I let that be.) Then did you read it well? Or didn't you understand it (again)?
  3. Now it would be interesting to know if you agree with Markus' descriptions. 'Unrelated'? You simply do not see what the relation is. One could call SR a 'meta-theory': it describes how space and time transform when seen by different inertial observers. As we all observe physical phenomena in space and time, all fundamental laws of physics must pass the test if they are Lorentz invariant. If they are not, then they are not correct. An FTL signal does not pass the test, so an entanglement explanation that contains an FTL signal cannot work. That is the whole argument in a nutshell. Even QM must 'obey' special relativity, which it does, as QFT.
  4. And of course a +1 for Markus. At least I understand it a little more clearly now.
  5. That goes back to the old example where lightning strikes both ends a train simultaneously on both ends relative to an observer in the center. Oh my. In the entanglement situation we are discussing that different inertial observers, in your interpretation where there is a FTL signal, must see one signal (between the measurements) going into opposite directions, but taking the same trajectory. And now you come with an example with two signals, taking two different trajectories, one of the front of the train to the middle, the other from rear to the middle. And this has to do nothing with SR. SR is not about observers being at different locations. That can be handled just as well with Newtonian mechanics. Just take the signal velocity in account, and you are done. SR however is about the different observations by observers in different inertial frames of reference, i.e. observers that move (fast) relatively to each other. Do you know the difference between spacial distant events, and space-like separated events in SR at all? I thought so. Case closed. Ah. It only violates one of the two groundstones* of SR, without which SR would be thoroughly false. At the same time SR is essential to our understanding of QFT, it is the basis even of our classical understanding of electro-magnetism, it is practically essential for GPS and particle accelerators, it explains the colour of gold and the liquidness of mercury, etc, but yeah, the invariance of light speed is just a provisional conjecture. You have no idea how SR is one of the roots of our understanding of the physical world. Every fundamental law of nature must pass the criterion that it is Lorentz invariant, i.e. does not lead to inconsistencies when we apply SR. * BTW the second postulate is not that nothing can go faster than light, it says that the speed of light is invariant. That no material object can reach the speed of light is a conclusion of SR. He, 22 already! Do not eat too much popcorn...
  6. Nope. You said: For which I wanted an explanation. Then you said: And then I asked an example of information transfer, or a signal, that works without a transfer of energy and/or matter. So maybe I was a bit confusing, but I want two examples: One of "Different observers seeing signals going into different directions" and how this is "a well understood phenomenon of SR". Information transfer or signal, without any energy or matter involved. And both not using entanglement, because that would mean you are using your conclusion about entanglement as argument, with other words you would "beg the question". And I am still waiting for a reaction on my posting:
  7. Nope. An observer with a constant velocity compared to a defined inertial frame will observe distances, durations etc differently from an observer in that defined inertial frame. What is true is that when we have an inertial frame of reference, and an observer is moving with constant velocity relative to that inertial frame, then that observer is also in an inertial frame. But it is another one.
  8. So you mean the entanglement source and the detectors are in same inertial reference frame, in other words, they are at rest relative to each other? Then say so. Next step: is this a preferred frame of reference? A preferred frame of reference in this context would mean that only in this frame correct conclusions about what physically is happening can be drawn. Next step: according to SR there are no preferred inertial frames of reference. Still, all observers, whatever their speed and direction, agree on the physics about what is going on. (However they can differ on distances, durations, timely order of events, simultaneity etc.) That is against 1., so 1. does not apply: the inertial frame of the experiment is not a preferred frame of reference. Next step: if there is a physical signal from one measurement to the other, all inertial observers should agree on this signal, especially its direction. Next step: for some observers Alice's measurement was first (e.g. Daniel in Joigus' drawing), for others Bob's measurement was first (Carla). Next step: Daniel and Carla do not agree on the direction of a hypothesised signal. But as they, according to SR, should agree on the physics of the situation (in this case which measurement determines the other), there can be no signal. As you see, there is no influence whatever from the different observers. Italics: Nope. Every observer observes the measurements, but they do not agree with each other which was first. So there is no objective first. Just to be sure: that is only true when the measurements are space-like separated, in the SR meaning of that concept. Not just space separated. Which you are using in your next argument: Oh my! In SR we talk about inertial frames of reference, not about the position of observers in space! It is 'easy-peasy' for Alice, if she knows the distance to Bob's detector, to conclude that his measurement was at the same time as her measurement. If detectors and entanglement source are in the same inertial frame of reference, Alice and Bob can agree on which measurement was first (or if they were simultaneous). Obfuscation from your side again: you have changed the meaning of 'reference frame'. Or you have a total misunderstanding of SR. Or both. Nope. I say that for space-like separated events there is no objective order of events. And just observing does not change anything. Do you really think we are saying that Carla and Daniel change the 'objective' order events, and that in different directions?
  9. Again use of vague concepts. What does 'grounded' mean here? That the experiment happens to be done in an inertial frame? OK, obviously you need reading glasses. So in a large font, specially for you: Nobody claims that observers that are in other inertial frames of reference affect the experiment. The rest of your argument is BS. Observers in other inertial frames, like in Joigus' drawing, Carla and Daniel, see the space-like separated measurements, assuming they were simultaneous in the frame of reference of the experiment, in opposite timely order. Still they must agree on the physical interpretation of the measurements. A signal from one measurement to the other cannot fulfill this condition. And, BTW, Alice and Bob are in the same inertial frame as the experiment. So what was the difference? I said, an example without entanglement. Oh man... It is so simple. According to SR there is no preferred inertial frame of reference. But you take the FoR of the experiment as such. I think that is also the reason why you keep sticking to this stupid idea that we think that other observers somehow change the order of events.
  10. And, oh, by the way, I am still waiting for an example:
  11. So what is the difference between the entanglement experiment and the Alice and Bob scenario? What? SR is the theory of how observers in different inertial frames of reference see physical events. It is the theory about how events are seen across different reference frames. How often must I repeat this? No order of events is 'changed'. Observers in different inertial frames of reference just see them in different timely order, when events are space-like separated. So this is blatantly false: Again: the essential improvement of Aspect's experiment was that the measurements were space-like separated. And when the measurements are, then there will be inertial frames in which the timely order of the measurements is in one direction, and others where it is in the other direction. And that is exactly what I am saying. However, you use the inertial frame of reference of the experiment as a preferred frame of reference. Which is prohibited by SR, exactly as you say.
  12. So your answer on my question of giving an example of a signal that does not imply transfer of energy is "No, I do not have such an example". Try again. And do not forget: no begging the question. Another example as entanglement. Sigh. I nowhere said that results are changed because of 'outside observations' (I assume you mean 'observations by observers that move relative to the experiment'. Why are you so vague again and again?). I am saying, trying other words, there is no universally agreed timely order of the space-like separated measurements. The inertial frame of the experiment has no 'special authority': that would mean it would be a preferred inertial frame of reference, which is against SR. So different observers do not agree upon which measurement was first, and therefore about the direction of a signal.
  13. The measurements do not have to be 'at the same femto second' in the rest frame of the experiment. To be space-like separated is enough. As in Aspect's 'real world' experiment. Really? A real signal, i.e. transferring information (and therefore at least a minimum amount of energy)? Or will you beg the question, and will give entanglement as example? So, please, give an example of such a signal, but not concerning entanglement. Simultaneous according which observer? Simultaneity is not even agreed upon by different observers for time-like separated events. Only the timely order is.
  14. No, I noticed earlier, but I always give people the benefit of the doubt. Maybe bangstrom has some problems understanding texts, maybe he doesn't know SR, etc... But I already called him a troll much earlier: Page 14 .
  15. It is obvious what I mean: again you are obfuscating the discussion. Of course I mean it in the context of SR: all inertial reference frames are equally valid; none is privileged, not even the inertial frame where entanglement source and measuring devices are at rest. So if we have two events, e.g. two measurements, that are space-like separated, there is no fixed timely order. You are moving the goal posts. Yes, it is easy, just setup the experiment so that the measurements are time-like separated. But that was not what we are talking about. You are evading the point we are making. As you know, we say there is no message. And one of the ways of seeing that is that when the two measurements are space-like separated, the timely order is different for different observers. Signals have a direction. But a signal going into one direction for one observer, but in another direction for another observer makes no sense physically.
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