On Sun, Jul 28, 2013 at 1:34 AM, meekerdb <meekerdb@verizon.net> wrote:
On 7/27/2013 11:31 PM, Dan Asimov wrote:
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.
Right.
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.
No. It's not a matter of heating the slit. If you were "watching" with the right instrument you could see where the buckyball was going with enough resolution to say which slit it would go through.
Sure; but the material around the slit itself is such an instrument. The material is an observer if it and the buckyball exchange photons. Same with every other bit of matter in the room, though it becomes harder to correlate the photon with path information as you get farther away.
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.
The buckyball is entangled with the IR photons, that's why they provide information about it.
Yes, and the IR photons that interact with the material around the slit get entangled with it, so then the material is entangled with the buckyball. It's similar to the teleportation protocol: the buckyball and the IR photon form an entangled pair, then the photon interacts with the slit material (or any other matter it hits) analogous to a Bell measurement. The result is that the buckyball and the material form an entangled pair---not maximally entangled, but as the buckyball gives off more and more photons, the state depends more and more on the shared information with the other matter. When you trace it out by only looking at the position of the buckyball on the screen, the interference disappears. -- Mike Stay - metaweta@gmail.com http://www.cs.auckland.ac.nz/~mike http://reperiendi.wordpress.com