# Can an electron be in two places at the same time?

Discussion in 'Physics & Math' started by Mind Over Matter, Nov 1, 2011.

1. ### OnlyMeValued Senior Member

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I have, I think a problem with this...

It is certain that the theory does describe the colapse as a point like particle, but does that prove a dimensionless point like particle? We really have no way to measure directly anything at those scales. All of our measurements are statistical and based on a model that begins by describing the colapse as a point like particle. Thus that is the way the data winds up being interpreted.

I cannot see how if what you are suggesting, is a truely dimensionless point, that there could be either energy or mass associated with it. It becomes essentially mathematical abstraction.

Accepting the the math works out that way and stipulating that the mathimatically model is a very successful predictive tool, are you saying that in fact the particle aspect or nature of a subatomic particle, once the wave function has collapsed, is a dimensionless point?

3. ### ReikuBannedBanned

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Actually no. You are making the same mistake as the last poster. I never said this. I said experimentation varifies that electrons and other particles behave as though pointlike. By default, this must mean a collapse in the wave function must reduce to the same statistics.

5. ### ReikuBannedBanned

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This is what I said to Magneto. Now do you still think that is what I implied above?

7. ### OnlyMeValued Senior Member

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That's what I understood. I think sometimes in the back and forth I lose track.

8. ### ReikuBannedBanned

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It's ok. We all do at times.

9. ### ReikuBannedBanned

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Particles act also as observers on other particles. Two particle's can come very close. Before any observation is made on the system, let us say that two particles have both spin up and spin down simultaneously. Two particles which come arbitrarily close can interfere with each other so that they can define either a spin up or a spin down for each particle. This natural occurance in nature is called decoherence.

10. ### river

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therefore an electron cannot be at two places at once or at the same time

11. ### ReikuBannedBanned

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Statistically-speaking, quantum field theory predicts they can.

12. ### AlphaNumericFully ionizedRegistered Senior Member

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Justify your claim with actual rigorous field theory because I don't believe you.

13. ### ReikuBannedBanned

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Depends on interpretation of the superpositioning principle. I thought you would have agreed with my statement, do you really want me to write up on it?

14. ### ReikuBannedBanned

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In fact, I wouldn't need to write anything complicated. Let us say, for simplicity that

$|\psi> = \frac{1}{2}i|A>+\frac{1}{2}i|B>$

The physical interpretation (of course not all physicists agree with the physical interpretation), is that statistically-speaking this particle described by the state $|\psi>$ is one half in position $A$ and one half in position $B$.

Last edited: Nov 24, 2011

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16. ### AlphaNumericFully ionizedRegistered Senior Member

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I'm well aware of the superposition principle. That doesn't mean the particle is in two places at once. Nor is it a necessarily field theoretic concept, it's in non-relativistic quantum mechanics too.

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18. ### prometheusviva voce!Registered Senior Member

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I think you mean $| \psi\rangle = \frac{i}{\sqrt{2}}|A\rangle+\frac{i}{\sqrt{2}}|B \rangle$ otherwise $\langle \psi | \psi \rangle \neq 1$

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Thanks.

20. ### river

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of course , thats the thing , the macro is the order of quantum , doesn't surprise me

hence why we don't get galaxies , planets etc popping in and out in the macro world ( Universe )

21. ### HEXiTRegistered Member

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ah waves and particles??? how do you get a particle to look like a wave? well you have it travel in a spiral. from the front it will look like a particle, but side on it looks like a wave. it will then take on both properties of waves and particles.
it may be, if particles travel in pairs rotating round each other, but to the outside observer they would look like there traveling in straight lines but the reality is they may not be. they may be traveling a double helix but because the oscillation is so small we havent picked it up yet.

i have no proof of this as its just an idea i have been mulling over.