On Monday, August 20, 2018 at 11:18:41 AM UTC, Bruce wrote: > > From: Bruno Marchal <[email protected] <javascript:>> > > > > On 19 Aug 2018, at 21:36, Brent Meeker <[email protected] > <javascript:>> wrote: > > > > > > But Alice and the detector are not in a singlet state and when you > combine them in a product with the singlet state the result is no long > rotationally invariant. > > The rotational invariance of the singlet state has not been broken, and in > principle Alice can get back to it by quantum memory erasure, unless > collapse. > > > You didn't respond to my earlier post in which I discussed the symmetry > breaking occasioned by Alice's measurement interaction with the singlet > state. I copy the relevant parts of my earlier post here: > > "The fact that Alice's interaction with the state is unitary and can be > reversed does not mean that the original symmetry still exists in some > sense. If I place a large weight at some point on the circumference of a > bicycle wheel, the rotational symmetry of that wheel is lost. The fact that > I can reverse the process by removing the imposed weight does not mean that > the altered wheel is still rotationally symmetric in some wider view." >
*If you have time, can you explain what "rotationally symmetric", or not, means in this context? AG * > > and later in the same post: > > "It seems that you are basing your conviction that all physics is > ultimately local on the idea that all interactions are unitary > transformations of the universal wave function. But that is not sufficient. > You have also to postulate that the wave function itself is actually local. > And we know that that is not true. Because non-separable, that is, > non-local, states do actually exist within the universal wave function. As > Maudlin points out, the basing an argument for locality on the wave > function fails because the wave function itself is not a local object." > *Earlier, when I was arguing that the probability density of wf for double slit extends to plus and minus infinity (and therefore, at creation it occupies all space, sort-of expanding instantaneously), Brent criticized my claim as using unrealistic initial conditions, presumably because the screen has finite length), yet here you seem to agree with me. What, in your view, makes the wf a non-local object? AG * > > 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 [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.
