Cosmology of bigravity with doubly coupled matter
arXiv:1501.00864 · doi:10.1088/1475-7516/2015/04/026
Abstract
We study cosmology in the bigravity formulation of the dRGT model where matter couples to both metrics. At linear order in perturbation theory two mass scales emerge: an hard one from the dRGT potential, and an environmental dependent one from the coupling of bigravity with matter. At early time, the dynamics is dictated by the second mass scale which is of order of the Hubble scale. The set of gauge invariant perturbations that couples to matter follow closely the same behaviour as in GR. The remaining perturbations show no issue in the scalar sector, while problems arise in the tensor and vector sectors. During radiation domination, a tensor mode grows power-like at super-horizon scales. More dangerously, the only propagating vector mode features an exponential instability on sub-horizon scales. We discuss the consequences of such instabilities and speculate on possible ways to deal with them.
20 pages, 1 figure, references added
References in corpus (20)
- Resummation of Massive Gravity
- Beyond the Cosmological Standard Model
- Massive gravity: nonlinear instability of the homogeneous and isotropic universe
- Accelerated expansion from ghost-free bigravity: a statistical analysis with improved generality
- On couplings to matter in massive (bi-)gravity
- Some remarks on the notions of general covariance and background independence
- Stable and unstable cosmological models in bimetric massive gravity
- Ghosts & Matter Couplings in Massive (bi-&multi-)Gravity
- Measurement of the t t-bar production cross section in the dilepton channel in pp collisions at sqrt(s) = 7 TeV
- Lorentz-violating graviton masses: getting around ghosts, low strong coupling scale and VDVZ discontinuity
- Spontaneous Lorentz Breaking and Massive Gravity
- Degrees of Freedom in Massive Gravity
- Gravitational waves in bigravity cosmology
- FRW Cosmological Perturbations in Massive Bigravity
- The coupling to matter in Massive, Bi- and Multi-Gravity
- Cosmic expansion histories in massive bigravity with symmetric matter coupling
- Appearance of Boulware-Deser ghost in bigravity with doubly coupled matter
- Linear growth of structure in massive bigravity
- Cosmological perturbations in massive gravity with doubly coupled matter
- Cosmology in rotation-invariant massive gravity with non-trivial fiducial metric
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- Higuchi Ghosts and Gradient Instabilities in Bimetric Gravity
- Cosmological gravitational particle production of massive spin-2 particles
- Surfing gravitational waves: can bigravity survive growing tensor modes?
- Bimetric-Affine Quadratic Gravity
- A general theory of linear cosmological perturbations: bimetric theories
- Cosmological histories in bimetric gravity: A graphical approach
- Cosmology of Massive Gravity and its Extensions
- Hamiltonian cosmology in bigravity and massive gravity
- Gravitational wave propagation beyond general relativity: waveform distortions and echoes
- Polarized solitons in higher-spin wave dark matter