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All these classical ideas are pointless and obsolete today, because in quantum mechanics, the particles are completely different objects, defined by quantum motion of fields, not by the location of classical points (at least not in a causal field picture). The notion of a point particle was replaced by the more subtle notion of a quantum point particle, which has a probability amplitude to be at various places. This quantum point particle can reproduce the quantum field if it is allowed to go backward and forward in time.

Ron Maimon

That was quoted by Ron Maimon. From this - Can I gather that in reality, particles travel backward and forward in time or, is this just a mathematical expression or model?


marked as duplicate by dmckee Mar 26 '13 at 14:46

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  • $\begingroup$ A really full answer would have to address both parity violation and CP violation, but the short version is there are mathematical congruences between matter and anti-matter that essentially make anti-particles look like their not-anti partners "going backward in time" (but sometimes also viewed in a mirror). The quoted statement isn't wrong, but it is definitely incomplete and very pop-sci. $\endgroup$ – dmckee Mar 26 '13 at 14:49