On Wed, Oct 16, 2019 at 10:10 AM John Clark <[email protected]> wrote:
> On Tue, Oct 15, 2019 at 6:01 PM 'Brent Meeker' < > [email protected]> wrote: > > *> Well in practice he has to measure them in an orthogonal basis in order >> to erase the welcher weg.* > > > I don't quite see how but apparently you think that will result in there > being a difference between the two universes and thus you predict no > interference pattern will be seen when the photographic plate is developed, > but David Deutsch thinks bands of interference will be on that plate. I'm > not certain who is right but I'd give 2 to 1 odds that it's Deutsch. Well > know for sure before 2050, maybe much sooner. > In the delayed choice experiment, the decision whether or not to quantum erase the "which way" information can be made long after the original photons hit the screen and make their marks there. So decoherence has set in, and any parallel universes have necessarily become different in some ways. According to your interpretation, therefore, there can then be no interference, because the worlds cannot come back together. But we can restore the interference pattern by quantum erasing the which way information (e.g., by measuring in an orthogonal basis). So it is not a matter of whether there are differences between parallel universes -- it is whether or not the which way information still exists in some form or the other. Deutsch simply got the explanation of interference in terms of interactions between parallel universes wrong. 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 view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/CAFxXSLRt4ohRq8w5j9qzButHZQh5Gbr7EJCabCPOkDvjvGxYcw%40mail.gmail.com.
