Weakly-coupled metastable graviton

Abstract

A graviton of a nonzero mass and decay width propagates five physical polarizations. The question of interactions of these polarizations is crucial for viability of models of massive/metastable gravity. This question is addressed in the context of the DGP model of a metastable graviton. First, I argue that the well-known breakdown of a naive perturbative expansion at a low scale is an artifact of the weak-field expansion itself. Then, I propose a different expansion -- the constrained perturbation theory -- in which the breakdown does not occur and the theory is perturbatively tractable all the way up to its natural ultraviolet cutoff. In this approach the couplings of the extra polarizations to matter and their selfcouplings appear to be suppressed and should be neglected in measurements at sub-horizon scales. The model reproduces results of General Relativity at observable distances with high accuracy, while predicting deviations from them at the present-day horizon scale.

13 LaTex pages; 1 eps figure; v2 some errors corrected; results unchanged

References in corpus (8)

• Ghost Inflation
• Differentiating between Modified Gravity and Dark Energy
• Softly Massive Gravity
• Graviton Mass or Cosmological Constant?
• Strong coupling in brane-induced gravity in five dimensions
• Strong Coupling vs. 4-D Locality in Induced Gravity
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• Ringing the Randall-Sundrum braneworld: metastable gravity wave bound states
• Cargese Lectures on Brane Induced Gravity
• Short distance non-perturbative effects of large distance modified gravity
• On covariant long-distance modifications of Einstein theory and strong coupling problem
• A note on the wellposedness of scalar brane world cosmological perturbations
• Cosmological perturbations of brane-induced gravity and the vDVZ discontinuity on FLRW space-times
• Looking At The Cosmological Constant From Infinite--Volume Bulk
• Mass Screening in Modified Gravity
• Massive Gravity in Ads and Minkowski Backgrounds
• Leakage of gravitational waves into an extra dimension in the DGP model
• Constrained Perturbative Expansion of the DGP Model