On Sat, Dec 1, 2012 at 6:00 PM, meekerdb <meeke...@verizon.net> wrote:
> >>>> Again there is nothing special about an observer in this, the
>> same thing would happen if nobody looked at the film, or even if you used a
>> brick wall instead of film, because the important thing is not that the
>> photon makes a record (whatever that is) but simply that it is destroyed.
>> >>> But you can do the experiment with electrons too, and the electrons
>> are not destroyed.
> >>Good point. If electrons are used in the two-split experiment a brick
> wall probably wouldn't do, you'd need a metal wall. Brick is a pretty good
> insulator so you'd end up with 2 small negatively charged spots on the wall
> in slightly different places;
> >How would you get two charged spots? Would each have charge -e/2?
No, if many worlds is right then the universe splits every time a electron
goes through the slits, and that means there are now 2 universes and that
means there are now 2 electrons and 2 Brents measuring 2 negative charges
on 2 insulating walls in 2 slightly different positions. So the universes
are different and do not merge and no interference is found.
> The experiment was originally done with photographic film, so that each
> electron ionized a silver halide atom resulting in a silver spot on the
> Now it's usually down is some kind of detector that amplifies the effect
> of each electron. Neither one has anything to do with destroying the
You don't need to destroy the electrons you just have to arrange things so
that the effect the 2 electrons have on their universes is
indistinguishable, then the 2 universes will merge back together and
interference is produced. If you fire electrons at 2 slits and have
sensitive detectors mounted near one slit so a record is made of which slit
each of the electrons went through then the universe splits into two each
time a electron is fired and it does not recombine because the 2 universes
are different, one has a record of the electron going through slot X and
the other has a record of it going through slot Y, and so no interference
is produced on the photographic plate. But if there is no detector near a
slit or no record kept of which slit it went through then the universe
still splits when it goes through the 2 slits because the 2 are different,
the electrons are on slightly different trajectories, but when the
electrons hit the metal wall there is no longer any detectable difference
between the 2 universes and so they merge back together, but there is still
evidence that the electron went through slot X only and evidence it went
through slot Y only and this produces the interference effect.
>> the walls would not be the same and so the 2 universes would not be the
>> same and so they would not merge. However if it was a metal wall the
>> electrons would just join the general sea of free electrons in the metal
>> and there is no way even in theory to tell one electron from another. So
>> the walls would have the same charge and mass.
> But in an entangled electron pair experiment (EPR type) detecting the
> path of one electron destroys the interference pattern on the other leg.
> But also just absorbing one electron destroys the interference on the
> other leg.
Yes, if one electron is absorbed into the electron sea of a metal and the
other electron is not then obviously the 2 universes remain different and
so do not recombine and so no interference is found.
> To maintain the interference you have to absorb the electron at the focal
> point of a lens so that you not only don't detect the which-way
> information, you erase it.
I don't quite know how a lens enters into this but yes, if the which-way
information is not recorded or the record erased by whatever means then the
2 universes are identical and merge and a interference pattern is seen.
John K Clark
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