Quantum Electrons

[JohnB]

I'll put the question here as it would be embarrasing to put it into a "proper" science forum.

 

If under Quantum mechanics, an electron potentially exists everwhere in the Universe at the same time. And if it doesn't actually exist until we actually look at it. Then;

 

Why does the Universe need more than one electron?

 

As can be seen, my knowledge of Quantum mechanics is slightly less than my knowledge of.....well anything, really.

 

I came across the question recently and thought it an interesting philosophical/theoretical one.

[ydoaPs]

electrons are being observed all the time. so, it is vastly more likely than not that there is more than one electron.

[insane_alien]

its all to do with probabilities such as there is a very slight possibility that you are of the opposite sex but just never noticed before.

[timo]

I'll put the question here as it would be embarrasing to put it into a "proper" science forum.

Hey, we have theads like the "Shadows" one in the "Modern/Theoretical Physics" subforum and you are afraid to put a rather good (well, valid, at least) question on QM in the QM section? You don´t even claim that your idea must be true because it came to you when you were completely stoned last night and suddenly recognized how the universe works.

I think this definitely is a QM question (as a matter of fact, in can be even seen as a Modern Theoretical Physics question, but see below for that). And even though you seem to lack some basics of QM this thread should still belong there.

 

Why does the Universe need more than one electron?

I´ll send the easiest refutation to your idea ahead before I get into detail: If there was only one electron, the total charge you could have, say on a capacitor, would be 1.6*10^-19 Coulomb. You´d have to scale the wavefunction to the total number of electrons, at least.

Another problem would arise from electron-electron interaction. How would you expect two electrons to repel each other if there is only one?

 

And if it [an electron] doesn't actually exist until we actually look at it. Then ...

It does exists. Many people regard the wavefunction only as a probability function for finding the electron. This is not completely true. The wavefunction IS the electron*. The little point-charge you usually have in mind simply doesn´t exist as such.

 

*Yes, I am aware that the wavefunction is only a description for the electron. But the point of my argument was that the electron (and every other particle) is not what you expect when you come from classical mechanics.

 

If under Quantum mechanics, an electron potentially exists everwhere in the Universe at the same time.

Yes, it does. All of them do.

 

I wanted to start from classical QM going over many-particle QM to Quantum Field Theory, here. But while writing it I quickly figured out that putting almost two years of a university Theoretical Physics course in one thread completely overtaxes me. So before I directly jump to QFT I just want to make an additional remark why the "only one electron" idea wont work:

Assume you make two precise measurements on the electron´s position. One at t=0 and one at t=T. The first one measures the electron to be at x=0. Due to uncertainty the electron can have any momentum, now. But it´s velocity is still bound to be <c. So for the 2nd measurement you couldn´t measure the electron at any x>cT. In other words: Each time some pixel on your monitor appears, you have stripped the sun of all it´s electrons for a few minutes ...

EDIT: As a hint for certain people: Disproving Relativity with this shows much more creativity than the usual I-messed-up-the-coordinate-transformations method.

 

Now for QFT and the reason why I think your thread is actually quite good: In QFT you actually do describe each type of particle by a single field (hence the name). But in contrast to the classical description of an electron as a wavefunction, the total amplitude (squared) does not need to be normalized to one anymore. Also, you don´t kill the sun just because you switch on your monitor, here.

But you actually have problems defining what an electron is supposed to be at all, now. The definition of a particle becomes even more dizzy than the "it´s a wavefunction" picture from above.

 

You could call the electron field "the electron", so in this case your assumption that there might be only one electron would be correct. However, this definition of the electron would have little in common with what you´d expect an electron to be. And it´s simply not the common definition.

 

Summary: There must be more than one electron because of the definition of it.

 

Disclaimer: Unlike most of my other posts I am not completely certain of what I am saying here, as I am just beginning to learn QFT myself, atm. So any (competent) corrections are highly welcome.

[ydoaPs]

its all to do with probabilities such as there is a very slight possibility that you are of the opposite sex but just never noticed before.

well, this is the pseudoscience forum.

[insane_alien]

who was saying it was pseudoscience there is actually a slight possibility! i remember some mathematician worked it out but its a tiny possibilty roughly the same as another big bang starting off in you porridge at breakfast.

[JohnB]

Um, that's something else I wanted to ask about.........

[gnpatterson]

don't give up the single electron thoery just yet, you could say that it is the same electron but that it has traveled to the black hole at the end of the universe and traveled back in tome to the start of the universe and that it has done this once for every electron that we see.

 

You could then write a message (kilroy was ere) on the electron and see which electrons have the message on them thus deducing which electrons had been throught the universe before and after the one you marked.