On Mon, Oct 21, 2019 at 6:07 PM Bruce Kellett <[email protected]> wrote:
>> That statement is worse than false, you're talking logical nonsense. The >> photograph itself contains which way information, if the photo has no >> interference pattern then you know the photon went through one and only one >> slit, and if it does have a interference pattern then you know the photon >> went through both slits. So if you have the ability and really and truly >> want to destroy the which way information *AFTER* the photon hits the >> photographic plate (or screen) then you MUST destroy the photograph too and >> do so before anybody looks at it. In 1801 Thomas Young was not a fool and >> that's why he had no desire to destroy his screen *BEFORE *he looked at >> it, and that's why he saw a interference pattern; but it's true if he had >> he would have not seen a interference pattern, he would not see anything at >> all because there would be no screen to look at because he destroyed it. >> > *> I quote from the Xiao-song Ma et al. paper (Zeilinger group): "The > authors proposed to combine the delayed-choice paradigm with the quantum > erasure concept. Since the welcher-weg information of the atoms is carried > by the photons, the choice of measurement of the photons -- either > revealing or erasing the atoms' welcher-weg information -- can be delayed > until 'long after the atoms have passed' the photon detectors at the double > slit.* > Bruce.... it clearly said "*the photon detectors at the double slit*", and that detector, the one right at the double slit, is the very thing that produces the which way information that you may or may not erase! You're confusing the photon detector that is directly at the slit, with the far distant interference detector which could be a photographic plate or a screen or electronic device; that second detector will see or not see a interference pattern depending on if the which way information that the first detector has produced has been erased or not. And yes, the decision to erase or not to erase the which way information could be delayed for a billion years after it passed the first detector provided the two detectors were a billion light years apart. John K Clark -- 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/CAJPayv1b2RAt6BPR6FrLRXPe%3DiYWT44nCD3qVp8AWODtDiREJA%40mail.gmail.com.
