FRW Cosmological Perturbations in Massive Bigravity
arXiv:1403.5679 · doi:10.1103/PhysRevD.90.084003
Abstract
Cosmological perturbations of FRW solutions in ghost free massive bigravity, including also a second matter sector, are studied in detail. At early time, we find that sub horizon exponential instabilities are unavoidable and they lead to a premature departure from the perturbative regime of cosmological perturbations.
latex, 14 pages