A slow Galileon scalar field in curved space-time
Abstract
In this paper, we define covariant Galilean transformations in curved space-time and find all scalar field theories invariant under this symmetry. The Slotheon is a Galilean-invariant scalar field with a modified propagator such that, whenever gravity is turned on and energy conditions are not violated, it moves slower than in the canonical setup. This property is achieved by a nonminimal derivative coupling of the Slotheon to the Einstein tensor. We prove that spherically symmetric black holes cannot have Slotheonic hairs. We then notice that in small derivative regimes the theory has an asymptotic local shift symmetry whenever the noncanonical coupling dominates over the canonical one.
- Publication:
-
Physical Review D
- Pub Date:
- May 2012
- DOI:
- 10.1103/PhysRevD.85.103501
- arXiv:
- arXiv:1108.1406
- Bibcode:
- 2012PhRvD..85j3501G
- Keywords:
-
- 98.80.Cq;
- 04.50.Kd;
- 11.30.-j;
- 11.30.Er;
- Particle-theory and field-theory models of the early Universe;
- Modified theories of gravity;
- Symmetry and conservation laws;
- Charge conjugation parity time reversal and other discrete symmetries;
- High Energy Physics - Theory;
- General Relativity and Quantum Cosmology;
- High Energy Physics - Phenomenology
- E-Print:
- 13 pages, 1 figure. v2: Galilean invariant Lagrangians corrected and improved, comments on quantum properties added. v3: typos corrected, to appear in PRD