Wrong link? The abstract (full text is paywalled) says:
It is argued that, if the laws of physics permit an advanced civilization to create and maintain a wormhole in space for interstellar travel, then that wormhole can be converted into a time machine with which causality might be violatable. Whether wormholes can be created and maintained entails deep, ill-understood issues about cosmic censorship, quantum gravity, and quantum field theory, including the question of whether field theory enforces an averaged version of the weak energy condition.
I don’t see any connection to Alcubierre drives. Classic Kip Thorne, though.
Without even pretending to be anything other than an amateur layman in such questions, I found this on arxiv, quote:
We show that for particular choices of the shaping function, the Alcubierre metric in the context
of conformal gravity does not violate the weak energy condition, as was the case of the original
solution. In particular, the resulting warp drive does not require the use of exotic matter.
Therefore, if conformal gravity is a correct extension of general relativity, super-luminal motion
via an Alcubierre metric might be a realistic solution, thus allowing faster-than-light interstellar
travel.
(Lastly, if you’re wondering why I’m replying to you a lot, it’s just because you are a prolific commenter with whom I occasionally disagree.)
Wrong link? The abstract (full text is paywalled) says:
It is argued that, if the laws of physics permit an advanced civilization to create and maintain a wormhole in space for interstellar travel, then that wormhole can be converted into a time machine with which causality might be violatable. Whether wormholes can be created and maintained entails deep, ill-understood issues about cosmic censorship, quantum gravity, and quantum field theory, including the question of whether field theory enforces an averaged version of the weak energy condition.
I don’t see any connection to Alcubierre drives. Classic Kip Thorne, though.
looks embarrassed
I just grabbed a citation from someone talking about how the Caismir effect can be used to create negative energy (in the context of stabilizing wormholes.) I should probably have checked that, I would have found it wasn’t actually in the abstract.
Nevertheless! My point was that negative energy is pretty obviously physically possible, since it’s what predicts the Caismir effect working. (There has been some attempt to claim the CE is actually predicted by some other theories, but that’s not widely accepted.)
Wrong link? The abstract (full text is paywalled) says:
I don’t see any connection to Alcubierre drives. Classic Kip Thorne, though.
Without even pretending to be anything other than an amateur layman in such questions, I found this on arxiv, quote:
(Lastly, if you’re wondering why I’m replying to you a lot, it’s just because you are a prolific commenter with whom I occasionally disagree.)
looks embarrassed
I just grabbed a citation from someone talking about how the Caismir effect can be used to create negative energy (in the context of stabilizing wormholes.) I should probably have checked that, I would have found it wasn’t actually in the abstract.
Nevertheless! My point was that negative energy is pretty obviously physically possible, since it’s what predicts the Caismir effect working. (There has been some attempt to claim the CE is actually predicted by some other theories, but that’s not widely accepted.)