Key points are not available for this paper at this time.
It has been suggested that the acceleration of the Universe may be due to the backreaction of perturbations to the Friedmann-Robertson-Walker background. For a universe dominated by cold dark matter, it is known that the backreaction of superhorizon perturbations cannot drive acceleration. We extend this result to models with cold dark matter together with a scalar field. We show that the scalar field can drive acceleration only via the standard mechanism of a constant or nearly constant piece of its potential (i.e., a cosmological constant); there is no separate mechanism involving superhorizon backreaction. This rules out some models which have been proposed in the literature.
Kumar et al. (2008) studied this question.