On Wed, Jun 30, 2021 at 4:50 AM Lawrence Crowell < [email protected]> wrote:
> The argument is a bit difficult, but the dS vacuum has positive energy and > there is some probability of it tunneling to a lower value. In order for this to be possible, there must be some "landscape" of possible values for the vacuum energy. There is no evidence for any such thing. The data are best described by a cosmological constant -- that is, a fixed constant function. In order for there to be some "landscape", or some lower possible value for the vacuum energy, there must be some function that describes this. That would require a dynamical origin for vacuum energy, and be the opposite of a simple constant. Any theory that goes in this direction is necessarily unevidenced speculation, no matter how arcane the mathematics might be. It may do this "drip by drip" with Gibbon-Hawking radiation. I think Gibbon-Hawking radiation is rather like Unruh radiation. -- a test body in the expanding universe will experience radiation, but the vacuum energy does not decay, since the whole of spacetime is not filled with such radiation -- it is only in the presence of a test body that it is observable. Just like with Unruh radiation. The spacetime surrounding the accelerating body is not filled with radiation since the inertial observer does not see radiation. All he sees is the accelerated body emitting the occasional thermal particle. Bruce It could also transition into an anti-de Sitter vacuum. In that case the > vacuum energy is negative, but there are conditions for regular eigenvalued > orbits that define a minimum. That is a difficult subject involving the > moduli of hyperbolic geometries. So string theory is not needed to > understand this. In fact the de Sitter vacuum is "anti-string," and string > theory has nothing directly to do with the spectra of elementary particles > or the vacuum in the observable universe, That is except with colliding > black holes. > > LC > > On Monday, June 28, 2021 at 5:31:47 PM UTC-5 Bruce wrote: > >> >> Do you have any actual evidence that the deSitter vacuum is unstable? Or >> is this just a speculative idea based on the idea of a string theory >> landscape? >> >> Bruce >> > -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/CAFxXSLSbqtB8GjE7K_MdWejNP%2BGh5gUEz5mK4LshM69JeOW3GA%40mail.gmail.com.
