Science Alert October 13, 2023
Although the existence of closed time like curves is hypothetical, they can be simulated probabilistically by quantum-teleportation circuits. An international team of researchers (UK, Switzerland, USA – NIST, University of Maryland) leveraged simulations to pinpoint a counterintuitive nonclassical advantage achievable with entanglement. A metrologist prepared probes to input into an unknown quantum interaction. The goal was to infer as much information per probe as possible. If the input was optimal, the information gained per probe could exceed any value achievable classically. The problem was that, only after the interaction the metrologist could learn which input would have been optimal. The metrologist could attempt to change the input by effectively teleporting the optimal input back in time, via entanglement manipulation. The effective time travel sometimes failed but ensured that, summed over trials, the metrologist’s winnings were positive. According to the researchers their demonstrated that entanglement can generate operational advantages forbidden in classical chronology-respecting theories… read more. Open Access TECHNICAL ARTICLEÂ
Examples of chronology-violating particles traversing hypothetical CTCs… Credit: Phys. Rev. Lett. 131, 150202, 12 October 2023