1 research outputs found
Mimicking Lambda with a spin-two ghost condensate
We propose a simple higher-derivative braneworld gravity model which contains
a stable accelerating branch, in the absence of cosmological constant or
potential, that can be used to describe the late time cosmic acceleration. This
model has similar qualitative features to that of Dvali-Gabadadze-Porrati, such
as the recovery of four-dimensional gravity at subhorizon scales, but unlike
that case, the graviton zero mode is massless and there are no linearized
instabilities. The acceleration rather is driven by bulk gravity in the form of
a spin-two ghost condensate. We show that this model can be consistent with
cosmological bounds and tests of gravity.Comment: references adde