On Tuesday, November 5, 2019 at 4:10:21 PM UTC-7, Bruce wrote: > > On Wed, Nov 6, 2019 at 9:49 AM Alan Grayson <[email protected] > <javascript:>> wrote: > >> On Tuesday, November 5, 2019 at 1:11:21 PM UTC-7, Brent wrote: >>> >>> On 11/5/2019 9:21 AM, smitra wrote: >>> > On 05-11-2019 02:53, Alan Grayson wrote: >>> >> IIUC, as the temperature rises, interference in the double slit C60 >>> >> experiment declines, and eventually disappears. I don't think this is >>> >> really a which-way experiment because the interference disappears >>> >> whether or not which-way is observed. How does this effect the >>> >> collapse issue? Usually, IIUC, when interference ceases to exist, it >>> >> implies collapse of the wf. So, is the C60 double slit experiment >>> >> evidence for collapse of the wf? TIA, AG >>> > >>> > >>> > Consider the C60 moving through one or the other slit and then ending >>> > up at some spot x on the screen. If the state of the rest of the >>> > universe when the C60 takes on slit is |A(x)> and it is |B(x)> if >>> > another slit is taken, then the interference pattern locally at spot x >>> > on the screen will be proportional to Re[<A(x)|B(x)>]. So, if there is >>> > perfect which way information for C60 that arrive in the neighborhood >>> > of spot x on the screen, then the two environmental states will be >>> > orthogonal and the interference will vanish. >>> > >>> > In case of the experiment in a thermal environment, the C60 will >>> > suffer collisions with photons. >>> >>> It's not collisions with photons from the environment. The C60s are >>> heated in the experiment, so it is IR emission from the C60 that puts >>> which-way information into the environment. >> >> >> That's what I don't understand. If there's no detector focused on, or >> watching the slits, >> how can which-way information exist? All we observe is loss of >> interference without >> which-way information. What can we conclude from this? AG >> > > I thought I had explained that in my first post on this matter. If the IR > photon wavelength is short enough, detecting that photon enables one to > determine which path the C60 followed, or which slit it went through. >
Amazing if true. I assume the photon is emitted in random directions and, moreover, there's no observation of the slits. If so, how could this determine which-way? AG > As the C60 atoms are heated up, the IR wavelengths become shorter, and we > can determine which slit for a greater proportion of the photons. Hence the > interference disappears gradually as the temperature increases. We do not > even have to detect the IR photons -- their information is in the > environment, and that is sufficient decoherence for the interference to > vanish. > This I previously understood. But what is the big picture take-away from this phenomenon? 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 view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/ccd9eac0-f521-4611-bb30-991159bb2a5d%40googlegroups.com.
