Do you have a reference to that scientific journal describing the time travel that is of a sort that has a scientific explanation?....Time travel is always going to be fantasy, sorry.
I'm being pedantic,
So sorry Dave
,
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...but I'm definitely sure there has been papers describing possible ways time travel (i.e. going back in time) might be possible. They can be highly speculative regarding the phyiscs or somtimes involve impossible objects that in reality can never be made but they generally do work with the laws of physics we have. But the general concept seems possible (but very difficult) and not fantasy.
Plus we time travel, all of us, constantly.
Also I don't see what the 'paradoxical repercusions' are in
Sliding doors. It's two different timelines. One might suggest that the whole film is implying there is some sort of fate that guides you to some preferred destination...but then it only explored two timelines for our entertainment that made sense alongside each other. What about the many many others?
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Back on topic. Yeah, I'm more than happy to not just have SF just be hard Science Fiction. (In my mind SF stands for Speculative Fiction and has all sorts of subgenres attached to it - the broader our church is the better for the health of the literature and the readers).
Yes there are plenty of fantasy stories that play with time travel, as they clearly work with the tropes of the particular fantasy genre they are written in and the time travel is a mcguffin to allow some sort of plot in them. Yet without knowing what the story is about I'd first throw a story with 'time travel' into the 'SF' pile. (Hell, I'd even include
Star Wars, sort of, even although it's Space Opera that is more towards fantasy in the fantasy/Sci-Fi spectrum.)
Just read the story now.
I would call it SF - the time slip/alternative reality reminded me of the physicist David Deutsche description of what a time machine would be like to experience. Yes, no explanation given on how it could happen, and there are some elements that give it a modern fairy tale aspect (Miss Matie growing younger) But the slip is there so that the story can talk about segregation in the US, it's not a mcguffin to move the protagonist into a magical realm for sake of a colourful plot. Hence it's concept-driven and therefore orbiting in my SF genre IMHO.