Physics – High Energy Physics – High Energy Physics - Theory
Scientific paper
2006-07-17
JCAP 0608:012,2006
Physics
High Energy Physics
High Energy Physics - Theory
39 LaTex pages
Scientific paper
10.1088/1475-7516/2006/08/012
We discuss small perturbations on the self-accelerated solution of the DGP model, and argue that claims of instability of the solution that are based on linearized calculations are unwarranted because of the following: (1) Small perturbations of an empty self-accelerated background can be quantized consistently without yielding ghosts. (2) Conformal sources, such as radiation, do not give rise to instabilities either. (3) A typical non-conformal source could introduce ghosts in the linearized approximation and become unstable, however, it also invalidates the approximation itself. Such a source creates a halo of variable curvature that locally dominates over the self-accelerated background and extends over a domain in which the linearization breaks down. Perturbations that are valid outside the halo may not continue inside, as it is suggested by some non-perturbative solutions. (4) In the Euclidean continuation of the theory, with arbitrary sources, we derive certain constraints imposed by the second order equations on first order perturbations, thus restricting the linearized solutions that could be continued into the full nonlinear theory. Naive linearized solutions fail to satisfy the above constraints. (5) Finally, we clarify in detail subtleties associated with the boundary conditions and analytic properties of the Green's functions.
Deffayet Cédric
Gabadadze Gregory
Iglesias Alberto
No associations
LandOfFree
Perturbations of Self-Accelerated Universe does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Perturbations of Self-Accelerated Universe, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Perturbations of Self-Accelerated Universe will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-506479