Improving relativistic MOND with Galileon k-mouflage
Jun, 2011
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Abstract: (arXiv)
We propose a simple field theory reproducing the MOND phenomenology at galaxy scale, while predicting negligible deviations from general relativity at small scales thanks to an extended Vainshtein ('k-mouflage') mechanism induced by a covariant Galileon-type Lagrangian. The model passes solar-system tests at the post-Newtonian order, including those of local Lorentz invariance, and its anomalous forces in binary-pulsar systems are orders of magnitude smaller than the tightest experimental constraints. The large-distance behavior is obtained as in Bekenstein's tensor-vector-scalar (TeVeS) model, but with several simplifications. In particular, no fine-tuned function is needed to interpolate between the MOND and Newtonian regimes, and no dynamics needs to be defined for the vector field because preferred-frame effects are negligible at small distances. The field equations depend on second (and lower) derivatives, and avoid thus the generic instabilities related to higher derivatives. Their perturbative solution around a Schwarzschild background is remarkably simple to derive. We also underline why the proposed model is particularly efficient within the class of covariant Galileons.Note:
- 6 pages, 1 figure, RevTeX4 format
- 04.50.Kd
- 95.35.+d
- 95.30.Sf
- background: Schwarzschild
- derivative: high
- MOND
- solar system
- symmetry: Galilei
- gravitation: TeVeS
References(36)
Figures(1)