While the idea of time travel gives rise to discussions of topics ranging from science fiction to ethics, understanding the possible effects of time travel gives us a better grasp of the foundations of general relativity and quantum theory. Most work in the area has focused on the theoretical aspects of time travel, but there are also attempts to simulate the effects of time travel experimentally.
In physics, a time machine is known as a closed timelike curve (CTC). Basically, an object makes a loop through spacetime to interact with its past self. In a recent work published in Nature, a team simulated the possible effect of a time machine using polarized light. Since they couldn’t actually make a beam of light travel back in time, they used two separate beams of light, with one beam mirroring an earlier state of the other. Their focus was to study how quantum computers might be affected by a CTC.
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