Cosmic acceleration and the helicity-0 graviton

Journal Article · Sun May 15 00:00:00 EDT 2011 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.83.103516· OSTI ID:21502559

Rham, Claudia de; Heisenberg, Lavinia ^[1]; Gabadadze, Gregory; Pirtskhalava, David ^[2]

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1. Department de Physique Theorique, Universite de Geneve, 24 Quai E. Ansermet, CH-1211 Geneve (Switzerland)
2. Center for Cosmology and Particle Physics, Department of Physics, New York University, New York, New York, 10003 (United States)

We explore cosmology in the decoupling limit of a nonlinear covariant extension of Fierz-Pauli massive gravity obtained recently in arXiv:1007.0443. In this limit the theory is a scalar-tensor model of a unique form defined by symmetries. We find that it admits a self-accelerated solution, with the Hubble parameter set by the graviton mass. The negative pressure causing the acceleration is due to a condensate of the helicity-0 component of the massive graviton, and the background evolution, in the approximation used, is indistinguishable from the {Lambda}CDM model. Fluctuations about the self-accelerated background are stable for a certain range of parameters involved. Most surprisingly, the fluctuation of the helicity-0 field above its background decouples from an arbitrary source in the linearized theory. We also show how massive gravity can remarkably screen an arbitrarily large cosmological constant in the decoupling limit, while evading issues with ghosts. The obtained static solution is stable against small perturbations, suggesting that the degravitation of the vacuum energy is possible in the full theory. Interestingly, however, this mechanism postpones the Vainshtein effect to shorter distance scales. Hence, fifth force measurements severely constrain the value of the cosmological constant that can be neutralized, making this scheme phenomenologically not viable for solving the old cosmological constant problem. We briefly speculate on a possible way out of this issue.

• OSTI ID: 21502559
• Journal Information: Physical Review. D, Particles Fields, Vol. 83, Issue 10; Other Information: DOI: 10.1103/PhysRevD.83.103516; (c) 2011 American Institute of Physics; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ACCELERATION
APPROXIMATIONS
CONDENSATES
COSMOLOGICAL CONSTANT
COSMOLOGY
DECOUPLING
DISTURBANCES
FLUCTUATIONS
GRAVITATION
HELICITY
MASS
MATHEMATICAL SOLUTIONS
NONLINEAR PROBLEMS
PERTURBATION THEORY
SYMMETRY
CALCULATION METHODS
PARTICLE PROPERTIES
VARIATIONS