On Friday, April 27, 2018 at 4:24:44 AM UTC, [email protected] wrote: > > > > On Friday, April 27, 2018 at 1:43:30 AM UTC, Brent wrote: >> >> >> >> On 4/26/2018 6:21 PM, [email protected] wrote: >> >> >> >> On Friday, April 27, 2018 at 1:10:25 AM UTC, Brent wrote: >>> >>> >>> >>> On 4/26/2018 4:14 PM, [email protected] wrote: >>> >>> >>> >>> On Thursday, April 26, 2018 at 10:25:29 PM UTC, Brent wrote: >>>> >>>> >>>> >>>> On 4/26/2018 2:33 PM, [email protected] wrote: >>>> >>>> >>>> >>>> On Thursday, April 26, 2018 at 9:09:48 PM UTC, Brent wrote: >>>>> >>>>> >>>>> >>>>> On 4/26/2018 7:23 AM, [email protected] wrote: >>>>> >>>>> >>>>> >>>>> On Thursday, April 26, 2018 at 4:12:41 AM UTC, Brent wrote: >>>>>> >>>>>> >>>>>> >>>>>> On 4/25/2018 7:44 PM, [email protected] wrote: >>>>>> >>>>>> >>>>>> >>>>>> On Thursday, April 26, 2018 at 2:17:31 AM UTC, Brent wrote: >>>>>>> >>>>>>> >>>>>>> >>>>>>> On 4/25/2018 6:39 PM, [email protected] wrote: >>>>>>> >>>>>>> >>>>>>> *On its face it's absurd to think the SoL is invariant for all >>>>>>> observers regardless of the relative motion of source and recipient, >>>>>>> but it >>>>>>> has testable consequences. The MWI has no testable consequences, so it >>>>>>> makes no sense to omit this key difference in your historical >>>>>>> comparisons >>>>>>> with other apparent absurdities in physics. Moreover when you factor >>>>>>> into >>>>>>> consideration that non locality persists in the many worlds postulated >>>>>>> -- >>>>>>> assuming you accept Bruce's analysis -- what exactly has been gained by >>>>>>> asserting the MWI? Nothing as far as I can tell. And the loss is >>>>>>> significant as any false path would be. AG* >>>>>>> >>>>>>> >>>>>>> It's one possible answer to the question of where the Heisenberg cut >>>>>>> is located (the other is QBism). It led to the theory of decoherence >>>>>>> and >>>>>>> Zurek's theory of quantum Darwinism which may explain Born's rule. >>>>>>> >>>>>>> Brent >>>>>>> >>>>>> >>>>>> * I've always found the Heisenberg Cut to be a nebulous concept, a >>>>>> kind of hypothetical demarcation between the quantum and classical >>>>>> worlds. * >>>>>> >>>>>> >>>>>> That's the problem with it; it doesn't have an objective physical >>>>>> definition. Bohr regarded it as a choice in analyzing an experiment; >>>>>> you >>>>>> put it where ever was convenient. >>>>>> >>>>>> *What kind of boundary are we talking about, and how could the MWI >>>>>> shed any light on it, whatever it is? AG * >>>>>> >>>>>> >>>>>> In MWI there is no Heisenberg cut; instead there's a splitting of >>>>>> worlds which has some objective location in terms of decoherence. >>>>>> >>>>>> Brent >>>>>> >>>>> >>>>> The Heisenberg Cut is too vague and ill-defined to shed light on >>>>> anything, and to say the MWI is helpful is adding another layer of >>>>> confusion. AG >>>>> >>>>> >>>>> Decoherence is a specific well-defined physical process and it >>>>> describes the splitting of worlds. There is still some question whether >>>>> it >>>>> entails the Born rule, but at worst the Born rule remains as a separate >>>>> axiom. >>>>> >>>>> Brent >>>>> >>>> >>>> Let's say an electron goes through an SG device. IIUC, its spin state >>>> becomes entangled with the spin wf's of the device. How do you infer >>>> splitting of worlds from this? AG >>>> >>>> >>>> I don't. Why should I? >>>> >>>> Brent >>>> >>> >>> I could swear that you wrote above that decoherence describes the >>> splitting of worlds, so I gave you an example of decoherence >>> >>> >>> You didn't give an example of decoherence. Where's the decoherence in >>> an electron flying through a divergent magnetic field? >>> >>> Brent >>> >> >> That's what I figured you would write and maybe you're correct. I thought >> decoherence means that the wf of the system being measured, gets entangled >> with the wf's of the environment, in this case the SG device. Why is this >> not decoherence, and if it isn't, what is? TIA, AG >> >> >> Decoherence happens when the particle is detected in one path or the >> other, not when going thru the SG. It's a classic experiment to show that >> particle wf can be coherently recombined after going through SGs. So if >> you set up a detector on one leg of the SG then the world splits when there >> is a detection vs no detection. >> >> Brent >> > > I am not considering a singlet state; just an electron passing through a > SG device and being measured, spin up or down. Are you saying no > decoherence in this case? From what I gather from descriptions of > decoherence, it occurs when a measurement occurs, and the particle's wf > gets entangled with the measurement device. This is a detection, and I > think you're saying the world splits. If so, why would it? If there's no > detection for whatever reason, what are we to conclude? I would guess, > nothing. AG >
Maybe you thought I meant an electron flying through an SG device and NOT be measured. No, I meant a measurement of Up or Down, and I think whenever we have a measurement, there is decoherence. But why this leads to a splitting of worlds is above my pay grade. AG -- 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.
