Some Late-time Asymptotics of General Scalar-Tensor Cosmologies
| dc.creator | Barrow, John D. | |
| dc.creator | Shaw, Douglas J. | |
| dc.date | 2007-12-13 | |
| dc.date.accessioned | 2026-07-07T11:39:23Z | |
| dc.date.available | 2026-07-07T11:39:23Z | |
| dc.description | We study the asymptotic behaviour of isotropic and homogeneous universes in general scalar-tensor gravity theories containing a p=-rho vacuum fluid stress and other sub-dominant matter stresses. It is shown that in order for there to be approach to a de Sitter spacetime at large 4-volumes the coupling function, omega(phi), which defines the scalar-tensor theory, must diverge faster than |phi_infty-phi|^(-1+epsilon) for all epsilon>0 as phi rightarrow phi_infty <> 0 for large values of the time. Thus, for a given theory, specified by omega(phi), there must exist some phi_infty in (0,infty) such that omega -> infty and omega' / omega^(2+epsilon) -> 0 as phi -> 0 phi_infty in order for cosmological solutions of the theory to approach de Sitter expansion at late times. We also classify the possible asymptotic time variations of the gravitation `constant' G(t) at late times in scalar-tensor theories. We show that (unlike in general relativity) the problem of a profusion of ``Boltzmann brains'' at late cosmological times can be avoided in scalar-tensor theories, including Brans-Dicke theory, in which phi -> infty and omega ~ o(ϕ^(1/2)) at asymptotically late times. | |
| dc.description | 14 pages | |
| dc.identifier | https://arxiv.org/abs/0712.2190 | |
| dc.identifier | http://arxiv.org/abs/0712.2190 | |
| dc.identifier | Class.Quant.Grav.25:085012,2008 | |
| dc.identifier | doi:10.1088/0264-9381/25/8/085012 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/199901 | |
| dc.subject | General Relativity and Quantum Cosmology | |
| dc.subject | Astrophysics | |
| dc.title | Some Late-time Asymptotics of General Scalar-Tensor Cosmologies | |
| dc.type | text |