On Wed, Nov 6, 2019 at 9:49 AM Alan Grayson <[email protected]> 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. 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. 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/CAFxXSLRv1P%3DQtKJQFtZS9w%3D8JP%3DrGetTNVwiR9Co74cQr2J6EQ%40mail.gmail.com.
