Self Tuning Scalar Fields in Spherically Symmetric Spacetimes

Understand

We search for self tuning solutions to the Einstein-scalar field equations for the simplest class of `Fab-Four' models with constant potentials.

• We first review the conditions under which self tuning occurs in a cosmological spacetime, and by introducing a small modification to the original theory - introducing the second and third Galileon terms - show how one can obtain de Sitter states where the expansion rate is independent of the vacuum energy.
• We then consider whether the same self tuning mechanism can persist in a spherically symmetric inhomogeneous spacetime.
• We show that there are no asymptotically flat solutions to the field equations in which the vacuum energy is screened, other than the trivial one (Minkowski space).