I thought I posted this, or something akin to it, yesterday, but I can’t find it now, so I’m posting it (again?).
http://www.preposterousuniverse.com/blog/2014/05/05 Boddy, Carroll and Pollack have been re-examining how quantum fluctuations work in cosmology. Sean Carroll explains:
“In an expanding universe that has nothing in it but vacuum energy, there simply aren’t any quantum fluctuations at all. Our approach shows that the conventional understanding of inflationary perturbations gets the right answer, although the perturbations aren’t due to “fluctuations”; they’re due to an effective measurement of the quantum state of the inflaton field when the universe reheats at the end of inflation. In contrast, less empirically-grounded ideas such as Boltzmann brains and eternal inflation both rely crucially on treating fluctuations as true dynamical events, occurring in real time — and we say that’s just wrong.”
If this idea is right, which Carroll concedes, is some way from being established, it could cast serious doubt on the idea of eternal inflation. That should ruffle a few feathers.
