While some topologies for the Universe would imply a globally preferred frame, what’s really important for SR is that you have locally preferred frames. To determine a global preferred frame, you need measurements of some sort or another spanning the entire Universe. What if you’re measuring only a very small portion of it, say a billion lightyears or so?
What you would need would be some sort of “superluminiferous æther” with a definite rest frame which would be used by your ansible. Now, even if we suppose that such an æther exists, and that the Universe is of a preferred-frame topology, there’s no reason to suppose a priori that those two frames would be the same.
I’m pretty sure, by the way, that the question of causality is equivalent to the Second Law: If you can get an acausal information flow, you can reduce the entropy of a closed system, and vice-versa.
Got a cite - even a vague one? In the context of a Maxwell Demon information-processing interpretation of the Second Law, the claim’s not that implausible now I think about it, but I’ve never seen the connection made.
There’s a whole Nova episode on this and some related questions…
The offered proof, as I understand it… Given that quantum tunnelling makes possible FTL travel over very SMALL distances by some “particles”, including light…
The physicist claiming this converted a Bach (or Beethoven?) symphony audio recording into to a modulated laser signal, which was directed against a very thin, but theoretically light-proof barrier. On the other side of the barrier were sensors which would detect light that passed through the barrier through quantum tunnelling. Though only a small portion of signal got through, it was enough to play back what was recognizably the same recording when the signal was reconverted to sound.
His detractors had two points. 1. Does sending data over VERY short distances even count? 2. If you can’t predict what particles will tunnel (and in the right direction), you can’t reliably reconstruct useful information at the other end.
I haven’t a clue how solid his physics is, but I admire that he’s found a theorectical backdoor to FTL, and even has a music video to present as evidence.
Is the conclusion pretty much this? “Of all the possible counterintuitive propositions that some observer O might eventually come to accept, the LEAST ACCEPTABLE is that some O-observed event E is dependent upon some causative factor F, E existing prior to F according to O’s time-scale.”
–and as this is clearly and definitely entailed by C-limit violation, according to a theory that has repeatedly shown its predictive power, it follows that C-limit violation is as close to being logically excluded as a proposition can be (short of being self-contradictory in an analytic sense). Hence, “here’s how to go faster than light” is more than likely a one-way trip from scientific illiteracy to Kooksville.