joigus

OK, punch a hole in the universe and go somewhere else. Good luck.

You cannot reach speed of light. Requires infinite energy for massive bodies. Period.

First main reason is this: There are more.

That could work too.

Thanks for the visual help.

I think "fall through" are the key words.

I can't see how this could be wrong. +1. Eggs were around long before anything chicken-like was around. Whenever you decide a mature organism merits the definition of chicken, there must have been something before that already merits the definition of egg. I think it's check mate.

Wrong paragraph, wrong book. Nothing about categories there; nothing makes much sense there either in today's context. You still sound cathartic.

Yes, you can cut off your non-local couplings at a certain distance. An interesting idea could be assuming non-locality but cutting off at microscopic range. Somewhere in the junkyard of my mind I remember that idea. I must have read it somewhere. You would have unblemished Einstein locality and causality, but small violations for very small distances. You can play with the idea with some freedom. Take the non-local term that I gave you, \[f\left(x,t\right)=\int_{-\infty}^{\infty}daf\left(a\right)F\left(x-a,t\right)\] and make the range of f(a) as small as you want.

OK. I've been racking my brain about this for a while. You mean the Unruh effect, or the Rindler coordinates for flat space-time. Those are accelerated observers. The bare vacuum (non-interacting theory) is invariant under Lorentz transformations, and the dressed vacuum (dressed with interactions) I think also is, if I remember correctly. \[U\left(\Lambda\right)\left|0\right\rangle =\left|0\right\rangle\] \[U\left(\Lambda\right)\left|\Omega\right\rangle =\left|\Omega\right\rangle\] (you can also assume a phase á la Wigner) Mind you, temperature in GR is something that still has to be understood, I hope you agree. I also think there must be a deep connection between GR and QFT that requires understanding entropy in GR and accelerated observers in QFT more thoroughly. It seems that some people in the scientific community share your worries: http://www.scholarpedia.org/article/Unruh_effect#Persisting_controversies Count me in. Multiple universes makes me very unhappy too. But that's in the area of interpretation of the theory. There's ground for reasonable disagreement, I surmise. I do too.

Yes, you're right. Don't take me seriously. What I was saying there was in the spirit of parametrizing a problem, see if I can understand it better in terms of parameters. That's all. I have no idea if there could be a meaningful way to talk about something "happening" in that context. It would be very, very iffy. Just a "what if".

That's what many people say and I understand how they can say that, because it's a formidable conceptual mirage. The violation of Bell's theorem cannot be put into question. But this only means that it is totally impossible to even think consistently about Sx, Sz and S45º at the same time. That's the extremely subtle point that I have no hope of getting across ever, because everybody seems to be more willing to believe in magic than to seriously sit and think about the assumptions. I know full well I will never hear the end of it. It's been 20 years for me personally, and counting. The truth is even John Bell was very cautious about making big statements concerning the implications of his theorem. Feynman was too. However weird the correlations are (and they certainly are), they were there when the singlet state was prepared, they were there a Plank's time worth of time after, and they will still be there when the particles are received seconds later. And they will keep there for as long as the overall U(1) symmetry of the state is not broken by interactions. They are initial correlations. Strange, puzzling correlations, yes; but initial, and generated locally when the system cooled down to a singlet. I know I have a strong opinion about this. But it's a reasoned opinion and at no point contradicts what's experimentally known. It's a matter of what it is that you read into the data.

No, sorry. I don't. It's not the structure that's behaving differently; the observers are. What that has to do with the vacuum goes through my mind like neutrinos through a paper sheet. You had a very interesting observation (IMO) about macroscopic observers being deprived of completely reconstructing their own past world-lines (the way I understood your argument). I thought so and I still do. Debatable perhaps, but made sense to me. But then you went farther and farther afield into a dark territory I know nothing of, nor do I have any intuition of what you mean. I've never been there. Sounds to me like you're trying to build a nuclear power station with tinker-toy assembly pieces and you forgot the plutonium.

I don't see the connection. Observations are observer-dependent ==> There is no underlying structure in the vacuum ??? But this was about time, wasn't it?

I don't know. They must be in PS format when they come out, so LaTeX compilation no longer works on them. That's my guess.

May I also add, @michel123456, that the concepts of vacuum that you so much dislike is also what allows you to formulate plausible scenarios for known experimental physics? Vacuum Einstein field equations --> The Sitter universe Vacuum in QFT --> anomalous g-factor of the electron In the first case, it gives a prediction that escaped Einstein and that's been confirmed by measurements on supernovas. In the second case, it's the most astonishingly precise prediction that's ever been. (1 part in a billion) You're clutching at straws here.

OK. But, "something went wrong!!" or "that guy did it!!" doesn't help much, does it? What does it add to the ongoing argument? That's my question for you.

WADR, I don't tell architects (or people who've had proper training in the matter) how to make buildings because I know better. But if I did, I would have no complaint if they call me to task and ask me about structures, beam tensions, corrosion, aesthetics, etc. "I think your corrosion argument is a clumsy attempt to link chemistry with aesthetics" would not be good enough an argument by any standards. That would be a completely silly, indefensible intellectual position.

I will assume you've not been swimming in Lake Chad. No expert here, but I agree with most popular advice: See your doctor.

OK. To the risk of sounding ridiculous, I will try to enunciate my own negative principle of physics. And let's all have a laugh. Very much in the spirit of other negative principles (which, remember, are the most robust principles of physics): 1) There are no perpetuum mobile machines (of the 1st and 2nd kind) --> 1st, 2nd pple. of thermodynamics 2) There is no way to distinguish (at one point) whether you're falling in a gravitational field or at rest, or uniformly moving (Pple. of Relativity + Equiv. Pple. integrated in one) 3) There are no quantum xerox machines (you can't clone quantum states) |a> --> |a>|a> as output ... (there are others) In the same spirit, what about this?: 4) There are no perfect vacuum cleaners (there is no way to conceive the vacuum as a featureless scenario by removing elements from the physics in the equations until you end up with nothing) You must remove the equations of physics themselves. Can you do that? Theoretical physicists are so used to racking their brains formulating a plausible vacuum, that they would find your arguments very out of touch with physics indeed, @michel123456.

How do you vary zero, one, or infinity? I do see something on the left.

I concur with Strange. HUP has to do with mean square deviations from average value, not measurement effects. You can apply as a bound to preparations (non-disruptive, or filtering measurements). This has been discussed elsewhere in the forums. There are implications of non-commutativity and 2nd-kind measurements (disruptive measurements), but it's more subtle, and I'd rather not go into that. Too many different cases involved. Even preparations are more subtle. Classical quantum mechanics books get it wrong, on account of being too simplistic. It's generally discussed that you can prepare an electron with an arbitrarily accurate state of px, py, pz (because in the framework of the theory they're commuting). That's a theoretical fiction. You can collimate electron beams with a selected value of, say pz, but you cannot guarantee that px, py are exactly zero, if nothing else, for the very simple experimental reason that you must make your beams go through diffraction windows in the perpendicular direction in order to filter them. I think that lies at the core of why people like M. Berry and others are finding a richer structure in electron beams than the naive academic picture that they're plane waves. Among other things, they can generally encapsulate orbital angular momentum. There are parallel developments in optics (Laguerre-Gaussian, Hermite-Gaussian beams...). I'm not 100 % sure that what I'm saying is totally watertight as to electrons. I'm particularly interested to read @Strange and @swansont's take on this. Sorry if these comments stray too off topic.

My opinion is yes, GR would have been found without Einstein. It would have taken a different order of consecutive realisations about different aspects of the theory. The field equations would have been named the Hilbert equations for gravity, probably. Formulated in a more mathematical language, and taken some decades to infer everything about photons red-shifting and bending, etc. And had Einstein been a woman, it would have taken a decade longer for everybody else to realise that she was right. Had it been a guy in Papua New Guinea, we still wouldn't know. And had it been a woman in Papua New Guinea, we would never know.

T'was a joke, Studiot.

There's also "local hero", "local customs", which involve time and memory.