On couplings to matter in massive (bi-)gravity

By Claudia de Rham, Lavinia Heisenberg, Raquel H. Ribeiro. 2014

174 citations recorded by the source corpus.

We investigate the coupling to matter in ghost-free massive (bi-)gravity. When species in the matter sector couple covariantly to only one metric, we show that at one-loop these couplings do not spoil the special structure of the graviton potential. When the same species couples directly to both metrics we show that a ghost is present at the classical level and that loops destroy the special structure of the potential at an unacceptably low scale. We then propose a new ‘composite’ effective metric built out of both metrics. When matter fields couple covariantly to this effective metric, the would be Boulware–Deser (BD) ghost is absent in different representative limits. At one-loop such couplings do not detune the special structure of the potential. We conjecture that matter can couple covariantly to that effective metric in all generality without introducing any BD ghost below a cut-off scale parametrically larger than the strong coupling scale. We also discuss alternative couplings to matter where the kinetic and potential terms of the matter field couple to different metrics. In both cases we discuss preliminary implications for cosmology.

View Paper: https://www.semanticscholar.org/paper/47fd4838466155969e06eeb0e9e61a3ea211fc61

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Citations in the corpus

• Bimetric gravity is cosmologically viable (2015, background): “[48] Claudia de Rham, Lavinia Heisenberg, and Raquel H.”
• Cosmological tests of modified gravity (2015, background): “There is a coupling which removes the BD ghost in the decoupling limit [157, 158].”
• Born–Infeld inspired modifications of gravity (2017, unknown): “This mechanism is at work for instance in theories featuring a K-mouflage/Kinetic or Vainshtein screening (see for instance [135, 133, 91, 136, 204, 137, 85]).”
• Heavy spin-2 Dark Matter (2016, background): “This choice is without loss of generality since the theory treats the metrics symmetrically and, in the bimetric theory, standard matter fields can only couple minimally to one of the tensor fields without introducing ghost instabilities [20, 21].”