Undergrad Is Time Travel Really Possible: Can We Move Backward in Time?

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Time travel to the future is straightforward, as we naturally progress forward in time daily. However, traveling backward in time is widely considered impossible due to the constraints of general relativity. While theoretical solutions exist that suggest the possibility of time loops, they require unphysical conditions, such as negative energy, which do not occur in our universe. The consensus is that, despite intriguing theories, practical backward time travel remains unattainable. Thus, the concept of moving back in time is largely deemed unfeasible.
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How can we travel back and forth in time?

And is it really possible?
 
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Forward in time is easy. I go forward a day every day.

Backward in time is probably impossible. There are solutions to the equations of general relativity that permit it, but they are generally believed to be unphysical. That is, we can describe a universe with "loops" in it that allow you to cross your own history, but the distribution of mass and energy needed to create it is impossible (negative energies or other stuff that doesn't exist).
 
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In an inertial frame of reference (IFR), there are two fixed points, A and B, which share an entangled state $$ \frac{1}{\sqrt{2}}(|0>_A|1>_B+|1>_A|0>_B) $$ At point A, a measurement is made. The state then collapses to $$ |a>_A|b>_B, \{a,b\}=\{0,1\} $$ We assume that A has the state ##|a>_A## and B has ##|b>_B## simultaneously, i.e., when their synchronized clocks both read time T However, in other inertial frames, due to the relativity of simultaneity, the moment when B has ##|b>_B##...
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