Bruno: The differentiation can't go faster than light Richard: How is that consistent with the EPR experiments?
On Wed, Nov 5, 2014 at 12:26 PM, Bruno Marchal <[email protected]> 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. > > 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)). > > Bruno > > > Brent > > > Are not the chlorophyl molecule doing something similar when exploiting > quantum weirdness for optimizing the use of the photons? Can the plant > "know" the precise time of the absorption of the photons and get at the > same time a similar energy optimum? > > Plant would manage the energy of the sun without seeing, and without > saying, of course :) > > I profit from not having read a paper on non-locality in time to > speculate wildly, sorry .... > If you have a good link on this form of non locality... (and if I can > optimize the energy and time needed ...) > > Bruno > > > > -- > 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. > > > http://iridia.ulb.ac.be/~marchal/ > > > > -- > 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. > -- You received this message because you are subscribed to the Google Groups "Everything List" group. 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