Gravitational potential evolution in unified dark matter scalar field cosmologies: An analytical approach

摘要

We investigate the time evolution of the gravitational potential Φ for a special class of non-adiabatic Unified Dark matter Models described by scalar field Lagrangians. These models predict the same background evolution as in the ΛCDM and possess a non-vanishing speed of sound. We provide a very accurate approximation of Φ, valid after the recombination epoch, in the form of a Bessel function of the first kind. This approximation may be useful for a future deeper analysis of Unified Dark Matter scalar field models.