On Wed, Apr 27, 2016 at 1:50 AM, Brent Meeker <[email protected]> wrote:
> > > On 4/26/2016 10:29 PM, Jesse Mazer wrote: > > > > On Tue, Apr 26, 2016 at 11:51 PM, Brent Meeker <[email protected]> > wrote: > >> >> >> On 4/26/2016 8:38 PM, Jesse Mazer wrote: >> >>> OK, let's say experimenter A measures particle 1, and experimenter B >>> measures particle 2. Any given copy of particle 1 has a "label" that says >>> something about the state of 2--we can imagine that the copy of particle 1 >>> carries a little clipboard on which is written down both its own quantum >>> state, and a quantum state it assigns to particle 2. When that copy of 1 is >>> measured, it not only adjusts its own state (to an eigenstate of the >>> measurement operator), it also adjusts the state it has written down for 2. >>> You seem to be assuming, in effect, that when a copy of 1 adjusts what it >>> has written down for the state of 2 on its own clipboard, this must mean >>> that copies of 2 also instantaneously adjust what they have written down >>> about *their* own state. However, in a copying-with-matching scheme, >>> there's no reason this need be the case! >>> >> >> That's pretty much the many-universes model that Bruno proposes. But it's >> non-local in the sense that the "matching scheme" must take account of >> which measurements are compatible, i.e. it "knows" the results even while >> they are spacelike separated. >> > > Why do you say that? Do you understand that in the type of scheme I am > talking about (and Mark Rubin too, I think), no "matching" between copies > of measurement-outcomes at different locations takes place at any location > in spacetime that doesn't lie in the future light cone of both measurements? > > > I think I understand it. Consider a spacelike slice that contains the > earliest overlap of the A and B measurment events forward lightcones. On > this slice the proper correlated results must obtain, which means that > observers at opposite sides of the lightcones from the overlap must also > observe the proper correlation - even though they are spacelike relative to > the overlap and spacelike relative to one of the measurement events. > I think you're misunderstanding--if we imagine a cellular-automata-like implementation where we have separate computers calculating the state of each small region of space, it's not as if a mapping calculated by a computer at one point in a spacelike slice needs to be instantaneously transmitted to all the other computers in that same spacelike slice. Correlations don't need to obtain across entire spacelike slices, information about mappings is itself local information associated with particular copies of localized systems (like copies of an experimenter that has received signals about two different measurements--each copy of this experimenter has a state that is determined by the outcome of both measurements, and hence qualifies as a physical 'mapping' between particular copies of the measurements themselves) Jesse -- 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 https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
