Backwards Time Travel Would Create Spooky, Self-Annihilating Twins

It's a common trope in science-fiction novels: Astronauts travel back in time by zooming through space at speeds faster than light
(usually getting into trouble in the process).
Most physicists think that scenario is impossible.
But let's suspend disbelief for a second. If it time travel like this were possible, how exactly would it work?
It turns out that objects traveling faster than the speed of light could go back in time — but in the process, a pair of phantom doubles of the
speedy object would pop out of thin air, and one would then go backwards and be annihilated with
another, according to one hypothesis, which Robert Nemiroff, a physicist at Michigan Technological University in Houghton, Michigan, described in a paper published in May in the
preprint journal arXiv .