On Thursday, November 6, 2014 7:38:29 AM UTC, Brent wrote: > > On 11/5/2014 9:26 AM, Bruno Marchal wrote: > > > On 04 Nov 2014, at 22:47, meekerdb wrote: > > On 11/4/2014 9:23 AM, Bruno Marchal wrote: > > > On 02 Nov 2014, at 19:09, meekerdb wrote: > > On 11/2/2014 1:27 AM, Bruno Marchal wrote: > > > On 01 Nov 2014, at 23:52, meekerdb wrote: > > Are you aware of the Paul-Pavicic "bomb" detector? > > http://cds.cern.ch/record/395858/files/9908023.pdf > > > I did not know this. Impressive. > > > > It is most easily thought of as non-local in time. > > > I will have to think about that. If you can elaborate. I think I intuit > what you are saying, but well, I need to work more on this. > > > Intuitively a photon is encouraged to enter the detector because it is in > resonance with an earlier instance of itself that is already circulating in > the detector. The experiment has not actually been done; but I think it > would not work if you determined the time of emission of the photon to a > precision on the order of the circulation time in the detector. > > > Is this based on some (relativistic?) account of the energy-time > "uncertainty relation"? > > I must confess I have some difficulty to grasp your explanation but that > might be due to my incompetence. > > > More likely a misfire of my intuition. I base it on their analysis which > just takes classical analysis of a continuous EM wave of a single frequency > (they note that a CW laser can have a 300Km coherence length so this is a > good approximation). So the solution is an EM field which is constant in > time, modulo the traveling phase. Then they interpret this as a > probability amplitude for a single photon. This implicitly makes the > probability amplitude for that single photon dependent on the wave that is > assumed to be time invariant. But then if you push the quantum viewpoint > further, that classical wave is just a probability amplitude for photons > that came earlier. > > > OK. > > > > Of course like most quantum weirdness the weirdness comes from assigning > an interpretation that explicitly splits the wave and particle pictures. > > > Is that not exactly what does the Copenhague dualisme, or von Neumann > projection? Hmmm ... ? > > > > http://arxiv.org/pdf/1112.4522.pdf > > > > No problem with that paper. As I am a bit skeptical about non-locality, > I am, like the author, certainly annoyed by the language making people > believing that there is some retro-causality involved in delayed choice > experiment. > > > I don't know why you should be bothered by that. The equations are time > symmetric and the direction of time is very likely just a statistical > feature; so if there are small reversals in isolated systems that's just > what one would expect. >
A difficulty for me with time as not what it seems and not substantive as it actually is. Well....what about the way time exchanges and rotates with things like light, mass, dimensionality, time for one person, time for the other. It doesn't look to be the way things would need to be if it didn't have fundamental secrets to discover. But it might not...but with so much unexplained and nothing really satisfyingly explained....I just think surely better to keep it all equal if unknown and keep everything in play, unless taking it out adds dramatic new knowledge for its loss. That's just opinion but if you do got a view on the time as complex at relative speeds or whatever....I would gladly hear it! > > > Now I will try, perhaps with my students, to get some "clearer" > many-world pictures of such non-locality in time. > Note that the usual Bell type of spatial non-locality is a non-locality in > time for any observer in motion with respect to Bob and Alice. In the > relativist frame, non-locality is always space-time non-locality. > > I just saw that Weinberg (in his "lectures on QM") seems to believe that > the MWI is automatically non-local, but I guess he points on the MW > theories which assumes some instantaneous split of the entire universe. > This of course makes no sense. The splitting, or differentiation, goes at > the interaction speeds. Superposition are contagious, but not so much as > becoming instantaneous. The differentiation can't go faster than light. > > I saw also that he attributes to Nicolas Gisin a theorem showing that if > we make the SWE slightly non linear, we get the possibility of non local > interaction between separated observers, that is, instantaneous action at > distance. He does not refer to its own similar result. That Weinberg's book > is very nice, if a bit short on Bell, QC and foundations, (but then it is > nice it refers to that matter, don't avoid Everett, nor Bell, and there are > other good books on that topics (like Hirvensalo, for mathematicians, > perhaps, or the Gruska book, for Quantum Computation)). > > > I just read last week that Weinberg had tried various ways of generalizing > QM and he only found one that really worked and it turned out to be a > rediscovery of and operator form of classical mechanics that had already > been developed by Koopman and von Neumann. KvN mechanics is essentially QM > on phase space with the assumption that all variables commute. I wonder if > it would be a good way to lead students into QM, assuming they were well > grounded in classical mechanics. > > You should look at how Vic Stenger gets QM in "The Comprehensible > Cosmos". I think you already have that book. > > Brent > -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
