On Fri, Nov 29, 2019 at 7:15 PM Philip Thrift <cloudver...@gmail.com> wrote:
> On Thursday, November 28, 2019 at 5:50:18 PM UTC-6, Bruce wrote: >> >> On Fri, Nov 29, 2019 at 1:27 AM Bruno Marchal <mar...@ulb.ac.be> wrote: >> >>> On 26 Nov 2019, at 22:39, Bruce Kellett <bhkel...@gmail.com> wrote: >>> >> >> I think it is becoming generally accepted in the physics community that >>> the entangled state is intrinsically non-local: acting on one part of it >>> affects the rest, even across the entire universe. >>> >>> >>> That would mean some FTL actions, but I very much doubt this. >>> >> >> No, there is no need of FTL. For example, in the third (2011) edition of >> his book 'Quantum Non-Locality and Relativity', Maudlin shows that Flash >> GRW theory, as developed by Tumulka, gives a perfectly relativistic >> account of the EPR correlations without any FTL action. >> >> Bruce >> > > > *The GRW flash theory: a relativistic quantum ontology of matter in > space-time?* > https://arxiv.org/pdf/1310.5308.pdf > > whenever there is a spontaneous localization of the wave-function in > configuration space, that development of the wave-function in configuration > space represents an event occurring in physical space, namely there being a > flash centred around a space-time point. The flashes are all there is in > space-time. That is to say, apart from when it spontaneously localizes, > the temporal development of the wave-function in configuration space does > not represent the distribution of matter in physical space. It represents > the objective probabilities for the occurrence of further flashes, given an > initial configuration of flashes. As in BM, there hence are no > superpositions of anything existing in physical space. However, by contrast > to BM, GRWf does not admit a continuous distribution of matter: there are > only flashes being > sparsely distributed in space-time, but no trajectories or worldlines of > anything > > > Over and above the flashes being the primitive stuff in physical space, > the initial configuration of flashes instantiates a dispositional property > – more precisely a propensity – that fixes probabilities for the occurrence > of further flashes. The occurrence of such further flashes is the > manifestation of that propensity. The propensity of any given configuration > of flashes to manifest itself in the occurrence of further flashes is > represented by the wave-function. The GRW law supervenes on that propensity > in the sense that whenever such a propensity is instantiated in a possible > world, the GRW law holds in that world. By contrast to what is admitted by > Humeanism, that disposition or propensity hence is a modal property. > > ... > > In conclusion, one may go for an event ontology instead of a particle > ontology. But the > flash ontology is too sparse an ontology: since it does not provide for > anything like > continuous sequences of events, it does not have the means at its disposal > to account for > interactions that are supposed to trigger the occurrence of further > flashes (such as e.g. > measurements). In the end, therefore, it seems that the flash ontology > hardly is a convincing > answer to the question of what quantum mechanics tells us about what there > is in space-time. > Which is not to say that there is anything clearly wrong with the GRW -flash idea: it is just that Esfeld and Gisin do not like it much. Bruce -- 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 everything-list+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/CAFxXSLTROdOpWzjSyCjqO6-3%3DCc0ycLmijx3U3ApRouxCaDABQ%40mail.gmail.com.
