Theory Seminar

On the Stability of Bimetric Cosmology

by Marcus Högås (Stockholm University)

Main/0-174 - Auditorium (Main)

Main/0-174 - Auditorium


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Bimetric gravity is a theory of two interacting spin-2 fields. It can reproduce the accelerated expansion of the Universe, without a cosmological constant. However, the stability of these solutions to linear perturbations has been questioned, suggesting exponential growth of structure in this approximation. We present a simple model of structure formation, for which an analytic solution is derived. The solution is well-behaved, showing that there is no physical instability with respect to these perturbations. The model can yield a growth of structure exhibiting measurable differences from ΛCDM.