This seems like an interesting article, but I found it very difficult to read. For example, from the introductory paragraph:
This literature equates the possibility of time travel with the existence of closed timelike curves (CTCs) or worldlines for material particles that are smooth, future-directed timelike curves with self-intersections.[3] Since time machines designate devices which bring about the existence of CTCs and thus enable time travel, the paradoxes of time travel are irrelevant for attempted “no-go” results for time machines because these results concern what happens before the emergence of CTCs.[4] This, in our opinion, is fortunate since the paradoxes of time travel are nothing more than a crude way of bringing out the fact that the application of familiar local laws of relativistic physics to a spacetime background which contains CTCs typically requires that consistency constraints on initial data must be met in order for a local solution of the laws to be extendable to a global solution.
I'm not sure what the intended audience for this is; combination philosopher physicists? Given that it's on SEP it seems unreasonable to assume that CTCs need no other explanation than that they are smooth, future-directed timelike curves with intersections. I would love it if someone would ELI5 this concept, though.
This literature equates the possibility of time travel with the existence of closed timelike curves (CTCs) or worldlines for material particles that are smooth, future-directed timelike curves with self-intersections.[3] Since time machines designate devices which bring about the existence of CTCs and thus enable time travel, the paradoxes of time travel are irrelevant for attempted “no-go” results for time machines because these results concern what happens before the emergence of CTCs.[4] This, in our opinion, is fortunate since the paradoxes of time travel are nothing more than a crude way of bringing out the fact that the application of familiar local laws of relativistic physics to a spacetime background which contains CTCs typically requires that consistency constraints on initial data must be met in order for a local solution of the laws to be extendable to a global solution.
I'm not sure what the intended audience for this is; combination philosopher physicists? Given that it's on SEP it seems unreasonable to assume that CTCs need no other explanation than that they are smooth, future-directed timelike curves with intersections. I would love it if someone would ELI5 this concept, though.