> On 25 Apr 2018, at 12:51, Bruce Kellett <[email protected]> wrote: > > From: Bruno Marchal <[email protected] <mailto:[email protected]>> >>> On 22 Apr 2018, at 01:47, Bruce Kellett < >>> <mailto:[email protected]>[email protected] >>> <mailto:[email protected]>> wrote: >>> >>> From: smitra <[email protected] <mailto:[email protected]>> >>>> >>>> On 22-04-2018 00:18, Brent Meeker wrote: >>>> On 4/21/2018 12:42 PM, smitra wrote: >>>> >>>> That's then an artifact of invoking an effective collapse of the >>>> wavefunction due to introducing the observer. The correlated two particle >>>> state is either put in by hand or one has shown how it was created. In the >>>> former case one is introducing non-local effects in an ad-hoc way in a >>>> theory that only has local interactions, so there is then nothing to >>>> explain in that case. In the latter case, the entangled state itself >>>> results from the local dynamics, one can put ALice and Bob at far away >>>> locations there and wait until the two particles arrive at their >>>> locations. The way the state vectors of the entire system that now also >>>> includes the state vectors of Alice and Bob themselves evolve, has no >>>> nontrivial non-local effects in them at all. >>>> >>>> Sure it does. The state vector itself is a function of spacelike >>>> separate events, which cause it to evolve into orthogonal >>>> components...whose statistics violated Bell's inequality. >>>> >>>> Brent >>>> >>>> There is no non-locality implied here unless you assume that the dynamics >>>> as predicted by QM is the result of a local hidden variables theory. >>>> >>>> Saibal >>> >>> There is no need to suggest local (or non-local) hidden variables. The >>> non-locality we are talking about is implied by the quantum state itself -- >>> nothing to do with the dynamics. >> >> >> But that type of non-locality has never been questioned, neither in the MWI, >> or a fortiori in QM+collapse. But the MWI explains without the need of >> “mysterious” influence-at-a-distance, which would be the case in the >> mono-universe theory, or in Bohm-De Broglie pilot wave theory. Without >> dynamic we have “only” d’Espagnat type of inseparability. >> >> Bruno > > It seems that you are starting to see it from my perspective.
We have already conclude that we agree. I have never doubt inseparability. The problem is perhaps just the term “non-locality”, which sometimes is claimed to mean “physical action at a distance in one branch of the multiverse”. > Non-locality is just another way of emphasizing the non-separablity of the > quantum singlet state. As you say, this is true in MWI as in collapse > theories. In my extended development of the mathematics in another recent > post, I demonstrated that there is actually no difference between MWI and CI > in this regard. In the prediction? I agree. But if there is a collapse, inseparability do entails some action at a distance, even it it cannot be used to send signal. > All that we have is the non-separability of the state, which means that a > measurement on one particle affects the result of measurements on the other > -- they are inseparable. “Affects” is ambiguous. Do you follow Bohr in saying that the action at a distance is not physical? But what could that mean? In the one-world assumption, it has to be as physical as the wave. In the MWI, it is only branch-self-localisation. > This is all that non-locality means, and this is not changed by MWI. In the MWI, we keep clearly d'espagant inseparability. But there is physical action at a distance, only the amoeba 1p-indeterminacy on which branch we belong. > An awful lot of nonsense has been talked about this -- people trying to find > a "mechanism" for the inseparability -- but that is not necessary. OK. (But assuming a bit of physical realism, you need the MW, it seems to me). > Quantum theory requires it, and it has been totally vindicated by experiment. > That is the way things are, in one world or many. In one world, I do not see how inseparability could not lead to action-at-a distance. In MW, I do not see why we would need a physical of mechanical action at a distance. Bruno > > 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] > <mailto:[email protected]>. > To post to this group, send email to [email protected] > <mailto:[email protected]>. > Visit this group at https://groups.google.com/group/everything-list > <https://groups.google.com/group/everything-list>. > For more options, visit https://groups.google.com/d/optout > <https://groups.google.com/d/optout>. -- 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.
