Quantum Accounting

An interesting article was linked from Slashdot this evening. It seems that some guys with some background in quantum physics have come up with a possible way around the grandfather paradox. In the article it is reported that they think that since the math seems to indicate that time travel is possible (under some pretty extreme conditions), there must be a solution to the grandfather paradox. Because quantum mechanics deals with probabilities, they are proposing that anything that has a probability of one when you leave will be something your presence in the 'past', for instance, you won't be able to prevent your own conception by killing your grandfather before you or your father is born.

This idea has a cool feel to it. It gives me the impression that time and thus causality as we see it isn't what we think. That time is not an immutable march forward, and that maybe everything, past and future, is really all the same thing, linked in a way we don't see because of the way we exist.

It has been proposed that the reason all atomic particles appear to be identical is because they are in fact the same particle, interacting with itself along a time-like dimension. When traveling in one direction through this dimension we see the particle as normal matter, when traveling in the other direction we see it as antimatter. This doesn't explain why antimatter seems less robust than normal matter, but its still an intesting idea, and fun to consider. If the idea has any truth to it, its probably at a much more fundamental level than we currently understand. For example, I'd expect that it would have to explain how virtual particle flux comes about, why there are so many kinds of quarks (I really expect that if there is a 'fundamental' particle, there is only one kind, all these different kinds of quarks doesn't seem very elegent to me. Maybe we're just looking at them the wrong way).

Its kind of sad to know that we'll never know for sure. I surely hope that the 'everlasting life' folks are right, but thats not where my money is laid.