Why is charge quantized the way it is?

Question

Quarks and the sign apart, all charged particles have the same charge (to incredible precision). The reason for that has not been known, at least until fairly recent times. Has there been any change in that, that anybody knows?

Answer 1

No--unless there's a magnetic monopole out there somewhere.  The existence of one in the universe guarantees that magnetic and electrical charge has to come in chunks (by some theorem of Dirac's)

here it is:

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

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yeah, that only explains why it would be quantized at all, not why it is quantized in the particular chunks it is in.  The ratio of the electric monopole to the magnetic monopole would still be a free parameter.  I heard a talk a while ago about all the attempts people had made to explain the fine structure constant (which is the same thing as explaining the fundamental charge).  There really isn't much promising.  One explanation from the more far-out models is that it's a free parameter that can assume any value when the universe is born.  Then, through the magic of the anthropic principle, it assumes the value it does because even a tiny variation would totally s***w up everything.  Nobody really LIKES anthropic arguments, but there's nothing better out there now that I know of.

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And per your quote about "arrogant, stupid answers", I honestly cannot believe you could say that after participating in a discussion with Fred.  Yeah, Archimedes didn't read the question, but come on.  His answer takes no cake whatsoever.  Fred's got the entire bakery.

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I guess I should add you.  I've been answering your questions because Remo stars them.

Answer 2

of course it's known - your "quantum"  is the charge on the electron.

All electrons and their charges are identical.

That's all you need to understand about this.