The answer is that they don’t literally go backwards in time showing reverse causality. They are representable in QFT by reversing the time component of their counterpart, which doesn’t impact how they interact with broader causality, just their internal configuration. Further - this does not play out in the lab as reversed causality even between anti particles. You can collide two positrons then detect them later at their destinations just fine in normal causality. It’s a shame because it would be really sweet to find some reversal of entropy and causality somewhere or somehow!
replyMay I introduce you to Maxwell’s Demon?
replyYou may, but if you read the link, you’ll find it consistent with the second law of thermodynamics despite being clever about it. The demonstration of consistency requires a modern understanding of information theory, but it’s been long realized it’s likely not a real “out.”
replyI'm too low energy to click on that link.
reply_We_ are still traveling forwards in time. If you followed a cloud of antiparticles backwards in time along its direction of travel, then you would see entropy decrease yes, though regular particles would do the same if we followed them back in time.
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