On the stability of bimetric structure formation

Understand

Bimetric gravity 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 analytical solution is derived.
• The solution is well-behaved, showing that there is no physical instability with respect to these perturbations.