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Ok, so, this is in the context of closed timelike curves. This is a thing which appears in the math of general relativity. It has never been observed in real life, and may disappear if we ever have a reconciliatian of quantum mechanics and gravity.
The study was a computer simulation of "what if we had some particles in a closed timelike curve and could mess with them", and there is no suggestion of this being applicable or even possible in the real world.