Jump to content


Senior Members
  • Posts

  • Joined

  • Last visited

  • Days Won


Everything posted by Eise

  1. Or Ethan Siegels blog, 'Starts with a bang'.
  2. I can't see the deadlock video('Something went wrong. Please refresh'). Could you post your diagram? I assume you understand deadlocks in one single RDBMS, but reading in itself usually does not lock any rows (except SQL Server when you are not running it in 'Read Committed Snapshot Isolation Level'. For Oracle this is the default isolation level. However, in a distributed transaction between 2 databases, the whole transaction must be prepared until the last 'commit readiness', in such a way that so to speak only one bit must be sent, meaning 'commit now'. This reduces the time gap that can occur via the network. Nothing is allowed to interfer in this time gap. Does that already help? Otherwise, be more specific. You diagram might help.
  3. Frequencies of what? Personally I think, no. The many worlds theory is based on the metaphysical assumption that the wave function is real, and never collapses, but instead splits into so many universes as there are possible outcomes of a quantum measurement. But as there is no possibility to know anything about all these 'other worlds' (except the one you find yourself in), the many worlds idea cannot be empirically tested. In other words, it is just an interpretation of QM. I belong to the 'epistemological camp': the wave function is not real, but with it we can calculate the probabilities of possible outcomes of a quantum measurement. We have no access to any deeper reality below that. Said in other words: with the wave function we have reached the limit of what we can know. Even an explanation of why the wave function works is then impossible: for that we would have to derive it from precisely this deeper ontological level to which we have no access. That said, interpretations can have heuristic value. Without pictures of what is 'really going on', it is difficult to think about QM. So interpretations can help to develop new ideas. As an example, Bell came to his theorem by thinking about Bohm's 'guide waves' theory, which is also an interpretation of QM.
  4. Then how do you explain that for the train frame the photons go vertical, but for you from the ground frame, according to you, the photons arrive back at the laser when the train is at the railway crossing? If you think a slant is needed, i.e. the observer/experimenter on the train must point the laser a bit forward, from the train frame it would miss the small mirror. Your viewpoint is logically inconsistent. There is no way the light clock would work for different inertial frames at the same time, including the rest frame of the light clock (the train). And I am shocked you are so sure about your viewpoint, where you obviously have no idea what vectors are, and how one adds them. But obviously you are not here to learn anything. I won't, because I am an 'amateur physicist'. But I am pretty sure the example of the wire and the length contraction is very simplified. I think it does nothing more than give a some intuition how special relativity, electricity and magnetism are related. E.g. from the example of the wire, I do not see how the magnetic field would be circular around the wire. Maybe some of the real physicists here can give a short comment on that? I have some notion of where the limits of my knowledge are. You obviously don't. You are saying that a theory that is already accepted and used for a century, and is basic to nearly all of fundamental physics, is wrong. Here is a list of empirical tests, that all confirm special relativity is correct. About the wire example, ChatGPT says the following: @swansont: is ChatGPT right?
  5. So here lies your problem. If the photons propagated also vertical in the ground frame, they would stick to the tree for you. The clock would not work anymore in the train frame. Of course now you will say that this can only be solved by pointing the laser in another, slanted direction. But why would the observer/experimenter do this? For him the photons return at the laser at the moment he passes the railroad crossing. That is my point 3 above, and you agreed with that. Furthermore the observer/experimenter on the train cannot do it for you in the ground frame and for the observer with a speed of 0.4c in the same direction as the train at the same moment. Which slant should he choose so you both see the light clock still working, because, as you agreed with, observing doesn't change anything (point 2).
  6. @Otto Nomicus: please go through my points one by one. So we can see better where our arguments deviate.
  7. Your whole argument has nothing to do with what I wrote. Please check what I wrote, and react on that. Genady's example however brought me to a better illustration than my first one. 1. So again we have the train with its light clock. In the train's frame it works perfectly, because the clock and the observer are at rest with respect to each other. Agree so far? 2. Now you are looking at the moving time clock from the ground referential frame. Would that affect if the light clock works? Of course not. Nothing changes in the train's inertial frame. Being observed or not from an observer in another frame of reference does not change anything. So the light clock still works fine. The light beam will not miss the small mirror just because it is observed from another referential frame. Agree so far? 3. What you in the ground frame can do now is mark the point on the railway where the light beam leaves the laser first. Just look, and e.g. it is exactly at a point where a tree stands. This is your first mark. Then mark the point where the light hits the mirror, e.g. where a signal pole is standing. And then again mark the point on the railway where you see that the light hits the laser again, e.g. a railway crossing. (Of course you have to turn your head to follow the train, and to mark the points on the railway, so you do not see a zig-zag line). Do you agree that such a procedure would be possible? 4. Now you measure the distances between the marked tree, signal pole, and railway crossing. So this is the real distance the train has traveled. And plotting the vertical distance of the light beam against these marked points, you will get a zig-zag line, this time independent on how you move your head, based on real distances. So no change of direction of the laser is necessary: just plot the position of the light against the railway track. And to extend on point 2: first you have to accept point 1: The light clock works perfectly from the frame of reference of the train. 2a. As an example, assume the train has a speed of 0.8c relative to the ground frame. Now we introduce a second observer, which travels at 0.4c in the same direction as the train. Both you and the second observer look at the light clock. Question for you: in which direction should the experimenter on the train point the laser so that: the light clock works for him the light clock works for you the light clock works for the second observer. If you say that this is impossible, then logically, you are saying that being observed changes the working of the light clock. Now you can choose to learn something by thinking my example through. Or you can bend in all kind of silly, wriggled arguments to show why you are right. Or you can just ignore my posting. The problem is that special relativity is used to design technologies, like GPS or particle accelerators, and explains things like the relation between electrical and magnetic fields, the colour of gold, the liquidness of mercury, and a lot more. Special relativity, which of course includes time dilation, is daily practice for many physicists, and so proven to the bone. So are you just discussing if the light clock example is a correct illustration of time dilation, or are you arguing against special relativity?
  8. No magic needed. Observing and seeing are not exactly the same. If I see that the moon is smaller than my hand, it doesn't mean that the moon really is smaller: I have to take into account that the moon is much farther away. So in the situation of the light clock I am not asking what you see (hey, you could move your head in the other direction, and you probably would 'see' that some velocities are above c. I am asking what according to you, in the ground frame, is the real distance the light beam travels in your frame of reference. (Hint: if you follow a moving car with your head, does that mean it has no speed? No, you must compensate for your own subjective view.) In fact, by turning your head, you are identifying yourself with the train frame. Turning a head is not part of what a frame of reference is. Maybe you should go back to Swansont's example, I hope at least that you now understand how he meant it. Must the person bouncing the ball on the train compensate for the velocity of the train, so that you see a zig-zag trajectory? And a final example: if somebody on a train throws a ball with a moderate velocity of, say, 20 km/h, and the train is moving 100 km/h, how fast is the ball flying according to you? 120 km/h? Or 20 km/h, because you moved your head to follow the train? And if he throws the ball out of the window, in the same direction as the train is moving, with which velocity will it hit a signal pole? 20 km/h, because you followed the train with your head? Or is it 120 km/h? (Don't try this at home, eh, in a real train. You know why...) PS Here is a link, that explains the light clock. Including a bouncing ball...
  9. Here is a youtube from '60 symbols' trying out ChatGPT: ChatGPT was a great help for me in writing a bash-script: it was not correct the first time, but everytime I wrote what the error was, ChatGPT came back with a better script, until it was correct. Today I tried it out with a SQL Server script, and I gave up after it was wrong again and again. It could still help in getting ideas though. Maybe there is more content in the internet about bash than SQL Server?
  10. It seems you did not understand Swansont's point: Let's try again with your laser and a train. On the very fast moving train, a light clock is clicking with a vertical 'bouncing' light ray from the laser. In the frame of the train the light clock of course stands still. That means the light beam always goes exactly vertically, because from the frame of the train the light clock is in rest, i.e. it is standing still. Now you, on the ground frame, you see the train passing by at high speed. This means you see a zig-zag line. The laser has not to point in another direction. E.g., imagine that the mirror is very small. In the frame of the train there is no problem: adjust the laser so that it points exactly at the small mirror i.e.the the laser is pointed exactly vertically downwards. As the train is standing still in its own frame, this can easily be done. Now you, from the ground frame, do you think you would see that the laser beam would miss the mirror? Of course not, that would be inconsistent. All observers agree on what is occurring physically, they just do not agree on when and where physical events happen, but they see the same physical events. That means for you,that you still see the laser is hitting the small mirror, just as for an observer on the train. But for you the train is moving, so you will see a the beam in a zig-zag line. And because this zig-zag line is longer than the vertical distance between laser and mirror, and c is still c, you see the light clock ticking slower. As Genady showed, you only need x = vt and Pythagoras to derive the correct formula for time dilation. And this time dilation is experimentally tested to the bone.
  11. Ha, @geordief: good point. With Markus, and David Hume, and Buddha, I would say it is "should" in its philosophical meaning, put otherwise, Descartes' argument is not correct. As Hume reflected, when we are aware of our thinking, we are always aware of something, like observations, thoughts, memories or feelings. But we are never aware of the ego as 'bearer' of these. I shortly looked into what Descartes really said, and the translation 'I think, therefore I am' seems the correct translation. Descartes wrote in Latin and in French. From here: French: In Latin: So both referring to 'I'. I don't know why it is always cited as just 'cogito, ergo sum'. Missing the 'I', resp 'ego' in it.
  12. Yep, "Papier hier" is correct. Phonetically you are very close with "Dank u Vell", correct spelling is "Dankuwel". Not so extreme as in German, but in Dutch we also glue words together.
  13. I know, therefore I just provided the link. I will not spend my time writing essays for people who refuse to understand what it is all about. But Chat PGT is of course funny, so here it is: It seems Chat PGT and Wikipedia pretty agree.
  14. Read the chapter as a whole and follow some of the links. You are asking basic questions about cosmology, which you can easily find in the internet. Wikipedia is always a good start. Or you could use Chat GPT...
  15. https://en.wikipedia.org/wiki/Big_Bang#Observational_evidence
  16. I don't know what the original language was, but I assume it was German. Here I found this German version: And that is 'parts'. But I am not sure how reliable that website is. But googling the whole sentence, I find a few other citations, but no other with the complete text, except other English translations. The few I looked at all say 'parts'.
  17. Yep. A version of ELIZA was implemented in Emacs: Wikipedia
  18. Thanks for the reference! I must assume now that @bangstrom is a pre-alpha release of ChatGPT, trained with the contents of the internet until about 1935 . However, I think that the program has some access to the internet. E.g. it knows that Zeilinger got the Nobel price. I assume it uses a Google API, picking some information that seems to fit to the contents of its pre-1935 training program, and somehow seems to support its position. It is clearly mimicking intelligence, but it is way behind its present Big Brother, ChatGPT.
  19. In which article of Bell? You made the citation, you should know. I did not find it, until now. You don't? If there were local hidden variables, there is no need for any signal. The electrons or photons would carry an attribute that would locally determine the measurement outcomes. SR is one of the best proven theories in physics, and essential in QFT, Electro-Magnetism, E = mc^2, and a hell of a lot more. It is intrinsic to the metric of spacetime. BS: From Wikipedia. Yes, no one is denying entanglement, but it only exists 'in the quantum world', and in QM there is no need for an FTL signal. Just a correlation that is greater than classically possible. Trying to understand this correlation classically, one would need an FTL signal. Ah, nearly forgot that you have reading problems. From the same article: Except the distance it is the same. Also in bound states the spin states are not determined, until measured, and they are just as well anti-correlated. Good. So now where do you still have problems with Markus' explanation? It must be somewhere, because it is clear his conclusion is that there is no FTL signal.
  20. John Bell? Less so: that is from the EPR-article. And you said somewhere 'EPR is invalidated' (whatever that means...) But now it supports your viewpoint? Wow. If you read the rest of the statement John Bell was listing in the quote the sort of things he considered “hidden variables’ in the EPR article and the hidden variables were what Aspect and Clauser ruled out as invalid fifty years ago. Seems you did not understand my remark. Your citation is from the original article by Einstein, Podolsky and Rosen. (That you claim is 'invalidated', whatever that means). It is not mentioned in Bell's 'Bertlmann's Socks'. And I fully agree that hidden local variables are ruled out. Right. Except that it was E, P and R's comment, not Bell's. But the absence of local hidden variables does not mean that the only alternative is an FTL signal. An FTL signal: does not appear in the QM that explains the correlation between the measurements, so you cannot build your argument for an FTL signal on QM. Markus explained this clearly in his post on page 22 is forbidden by SR in principle cannot physically exist because for observers in different inertial frames the direction of the signal can differ. That means they differ about the direction of the causal relationship between the measurements. But in SR all inertial observers agree in the direction of causal relationships. Really? You said: Italics by me. So the timing of the classical signal and the measurement are essential. Ask Zeilinger to do his 'teleportation' without classical signal. If you say it is not essential, then you can do without. (But why should the timing be so important...?) Nope. Complete false picture of entanglement. The particles are anti-correlated per definition of what entanglement is. We know the particles are entangled, so that they are anti-correlated. That is exactly what entanglement means: the particles are (anti-)correlated no measurement was done on the particles yet We just don't know what the measurements will result to, but if we have a pure singlet state, and we know the spin is up in one direction, then the other particle, measured in the same direction, will be down. But this is based on the correlation between the particles. And in QM this correlation is stronger than we can understand classically. So if you think classically, where such entanglement does not exist, we must conclude that there is a FTL signal. So your way of thinking is already more than 90 years outdated. Exactly the opposite: the singlet state is the fully entangled state. Exactly as Markus described. Please give an exact citation where Markus said that. You even agree: Now what is this 'hidden variable ruled out by the Bell test'? That the particles are entangled? Or is a hidden variable an attribute of the particles from the beginning, that determine which particle will show which spin? 🤣
  21. Which statement you mean? Please give this 'rest of the statement' and a link to the article where it comes from. Does teleportation work when you omit this preparation? If not, then the classical signal is essential. Nope. You must read it as 'quantum entanglement can only be understood by using quantum mechanics'. There is no FTL signal in the quantum mechanical explanation. QM entanglement cannot be simulated with classical means, unless you allow for FTL communication. And you evaded my first point. Here it is again for you: Oh man, trying not to loose your face, you now even have lost sight of what entanglement is. We know that the particles are entangled from the beginning, because they are produced entangled. Do you suggest to show entanglement is real by using particles that are not entangled from the beginning? That is the crux of the 'singlet state': we know the wave function of both particles together, but not of the individual particles. That means we know the outcomes of the measurements must be (anti-)correlated.
  22. From your link https://kiisfm.iheart.com/content/2022-05-09-best-photograph-of-a-ufo-ever-taken-has-experts-stumped/: I have read similar comments on a lot of UFO photographs. So I am all in for TheVat's '3rd alternative':
  23. Oh man, trying not to loose your face, you now even have lost sight of what entanglement is. We know that the particles are entangled from the beginning, because they are produced entangled. Do you suggest to show entanglement is real by using particles that are not entangled from the beginning? That is the crux of the 'singlet state': we know the wave function of both particles together, but not of the individual particles. That means we know the outcomes of the measurements must be (anti-)correlated. John Bell? Less so: that is from the EPR-article. And you said somewhere 'EPR is invalidated' (whatever that means...) But now it supports your viewpoint? Wow. The 'only purpose'? That 'purpose' is central for quantum teleportation to succeed. The classical signal is necessary for teleportation. But I fully agree with Markus that when discussing entanglement in itself, you should not use more difficult setups that make use of entanglement. If you think classically, yes. But that is exactly what the Bell theorem says: the only way one could simulate entanglement with classical means would need an immediate interaction between the entangled particles. As you think classically, you think it needs an FTL signal. Your arguments become worse and worse. Oh my, page 25...
  24. Oh, c'mon. c is the lightspeed through vacuum, not relative to vacuum. Yep, that is what characterises entanglement. The directions of the spins are anti-correlated, meaning that we know from the beginning that if we 'add the spins' (when measured in the same direction), we will get zero. Just as a remark, in some experiments, with photons e.g. the particles are correlated. But I'll go with your anti-correlated example, no prob. Nope. The 'hidden variables' ruled out by the Bell test are properties of the particles that determine in advance what spins will be measured. On one side, exactly, but you look with 'classical eyes' on entanglement. That is your problem. On the other side, no: besides the entangle particles needed in quantum teleportation, there is also a classical signal needed. You know that very well.
  25. In the US there are many more Republicans dropping dead than Democrats. Just guess why... Two hints: Which group was more vaccinated? Which group did take social distancing and masks more serious? The risks of Covid vaccination are negligible compared to having Covid. From More Republicans Died Than Democrats after COVID-19 Vaccines Came Out
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.