Thanks a lot, Mike. That definitely makes things a lot clearer (though not clear per se). But I'm fundamentally still confused with whether it's just radiation you see on the screen, or whether the buckyballs themselves ("going in the same direction") are moving toward the screen. (And hence whether the interference pattern is just one of radiation or of carbon molecules.) --Dan On 2013-07-27, at 11:11 PM, Mike Stay wrote:
On Sat, Jul 27, 2013 at 11:59 PM, Dan Asimov <dasimov@earthlink.net> wrote:
I don't understand what's going on here.
1) Are you really "directing" buckyballs (or radiation) at the screen, or just filtering out all but what goes through (one or both of) the two slits?
Buckyballs are usually made with something like an arc welder, so you filter out all but a few going in the same direction at the start. Then you put the double slit at some distance from the source.
2) I would've guessed that there'd be more, not less, infrared radiation as the temperature increases -- at least up to a point. No?
Yes---the hotter the particle, the more radiation.
3) Also, what does "which-way information" mean and how do IR photons provide that?
"Which-way" information is information that can be used to detect which slit the particles went through. An IR photon emitted when the buckyball is near a slit will heat up the material around the slit it goes through more than the material around the other slit.
4) Finally, why does the interference pattern fade away as you heat up the buckyballs?
Because the buckyballs get entangled with the slits, so the balls hitting the screen are in a mixed state (the slit information is "traced out") rather than a coherent state.