Re: Two-slit experiment

drspeg wrote:

I've been looking for an answer to two questions regarding the 2-slit
experiment (showing both wave and particle properties of light). I hope
someone here might know how to respond.

Quick review of what I believe I know: Shooting a single photon (or
electron) at a wall that contains two slits will result in an interference
pattern on the wall (detector plate) beyond the holes. Blocking one hole
results in an accumulation pattern. When both holes are open, detecting
which of the two holes the electron passes through results in an
accumulation pattern (uncertainty is violated).

A double slit pattern is not the sum of two single slit patterns. For
one thing, the double slit maximum is directly opposite the center
barrier. You can look it up in a physics text book,

http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html
http://www.motionmountain.net/

(1) Does obtaining an interference pattern depend at all on the timing of
the electron gun shooting each new electron? Or would the interference
pattern still obtain even if you shot one electron a day for many days (and
were able to record the impacts of electrons on the detector plate)?

Timing is irrelevant. Each individual moiety's wavefunction passes
through both slits - photon, electron, or huge giant really big
spatially extended rigidly multiply-connected massive lump,

http://www.quantum.univie.ac.at/research/matterwave/c60/index.html
C60 diffraction

(2) If, in the case where one determines through which slit each electron
passes, one were to replace the detector plate with ANOTHER wall containing
two slits, would uncertainty be restored? That is, knowing through which
slit electrons first pass should produce an accumulation pattern, but if
that pattern were displayed on a wall containing two slits (in this case the
experimenter does NOT determine through which slit the electron passes)
would an interference pattern occur?

Google
"quantum eraser" 15,400 hits

But why stop there?

http://en.wikipedia.org/wiki/Delayed_choice_quantum_eraser

So, in this double-two-slit experiment, determining the first "choice" made
by the pasing electron, but not the second... would there be an accumulation
pattern followed by an interference pattern?

Here's a nice Gedankenexperiment. We take an organic molecule that
degenerately rearranges at a tremendous rate, like semibullvalene
(Ea=5.5 kcal/mol),

http://faculty.juniata.edu/reingold/rsch.html
http://en.wikipedia.org/wiki/Semibullvalene
<http://csi.chemie.tu-darmstadt.de/ak/immel/tutorials/structures/index5.html>

and we do the C60 experiment with it. However... when we thin-film
fabricate the diffraction grating we apply an alternating Peltier
heater so alternate slits are cold and hot. When a semibullvalene
wavefunction passes through the slits it has different rearrangement
rates at the different temperatures. Find a set of conditions that
dephases the wavefunction by exactly 180 degrees slit vs. slit. When
the two halves recombine on the other side... destructive
interference! Where is the molecule?

--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz3.pdf

.

Relevant Pages

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