One-electron seems very problematic in light of the observed antimatter asymmetry. Why/how could the electron travel forwards in time more often than backwards?
Well, assume that time loops back onto itself. Then the electron goes forward most of the time and you see multiple copies. ( This is of course ridiculous, everybody knows that all electrons are just pointers to one const particle structure. )
Obtaining multiple electrons by forcing a single one to bounce back and forth all the way across the time line a zillion times seems like a major design smell. That would be the worst hack ever, or at least the worst one before Facebook devs hacked Dalvik just to get their app to run on Android: http://jaxenter.com/facebooks-completely-insane-dalvik-hack-... ;)
Perhaps our universe is one created by a junior, or an intern, and this "creative" workaround got mocked on TheDailyWTF somewhere.
Well, it's immutable. So why would it be a problem with bouncing it around?
It's like a symbol in Ruby -- all instances of, say, :electron point to the same point in memory, they're just used all over the place. The sharing isn't problematic because you can't change :electron.
Why would you want to use 'electron' instead where every time you use it, you put another instance of it into memory?
It's only a "major design smell" to "bounce back and forth" if it's computationally expensive. This theory makes it sound like electrons aren't firmly rooted in space and time to begin with.
Maybe it's computationally cheaper to define something as existing in all places and all times.
Well I imagine it isn't optimized for readability :)
If the point is to have a jillion of electrons, each at the right time and place (for the observer), I assume a rather complicated mechanism must have been put in place to "tie the knot" just right - I mean to "navigate" the time-travelling electron just so it never fails to appear wherever, whenever it's expected.
It would be terrible to design it that way, but I think it's fine as a compiler optimization. Most of that datastructure is constant anyway, think of the memory savings!
In that case there'd be no need to convert back-and-forth between electrons/positrons or forward/reverse time at all. The only requirement would be that the observed Universe is a fixed-point of this loop.
Well, perhaps it's only in our time frame. For instance, let's imagine that the electron goes forward from 0 to 5, then bounces back to 1, then to 5 again, and back to 2 etc.
If we were at 1.5, we would see it moving forward TWICE (0=>5 and 1=>5), but only returning ONCE (1<=5; we haven't gotten to observe 2<=5 yet).
Whether it's plausible I have no clue :) it just shows that in principle you can have local asymmetry while everything still balances out at the end.
That doesn't work because you've left the loop open. If the positron just goes back to 2 and stops, from our point of view it has just appeared from nowhere, which isn't physical.
In order to close the loop you have to go back to 0 and meet the original electron. Once you've done that you lose the asymmetry again.
Well, I won't pretend that I know how it's supposed to work, but even if the loop was closed, the electron (and the loop itself) still must have come to existence out of nowhere somehow, so it doesn't remove this ontological problem :)
I'm not really talking about an ontological problem though, I'm saying that an electron appearing on its own is a physical impossibility. Electrons must appear or disappear alongside a positron partner, which means that the idea of "local asymmetry" can't solve the symmetry problem.
