Ayasano
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I'm surprised nobody in this thread has mentioned delayed-choice experiments yet. I've only seen one mention of it on the forum (here) and it got no replies.
The gist of it is that in certain experiments like the double slit experiment, the quantum eraser experiment, etc., if you change whether the detector is present at a certain point after you start the experiment, it affects the result in a way that isn't possible without a small amount of retrocausaility. Don't get too excited though, because the way it works doesn't allow for you to violate causality or send information back or anything. But it does at least demonstrate that effect doesn't always have to follow cause. A paper on one such experiment can be found here.
If you want some solid theory behind real time travel, do a google search for "cosmic strings closed timelike curve", which brings up results such as this. (Not to be confused with string theory, although there is some crossover) There's some tenous evidence for cosmic strings to exist, but they're a bit difficult to actually wrangle for time travel purposes, you mostly have to hope you find one in the configuration you need. However, if conditions were right, they could allow for travel as far back as shortly after the Big Bang, though it might include a few stopovers.
The gist of it is that in certain experiments like the double slit experiment, the quantum eraser experiment, etc., if you change whether the detector is present at a certain point after you start the experiment, it affects the result in a way that isn't possible without a small amount of retrocausaility. Don't get too excited though, because the way it works doesn't allow for you to violate causality or send information back or anything. But it does at least demonstrate that effect doesn't always have to follow cause. A paper on one such experiment can be found here.
If you want some solid theory behind real time travel, do a google search for "cosmic strings closed timelike curve", which brings up results such as this. (Not to be confused with string theory, although there is some crossover) There's some tenous evidence for cosmic strings to exist, but they're a bit difficult to actually wrangle for time travel purposes, you mostly have to hope you find one in the configuration you need. However, if conditions were right, they could allow for travel as far back as shortly after the Big Bang, though it might include a few stopovers.