A Simplified Formalism for Computing Growth Rates for Perturbations in Standard Cosmology

Abstract

We present a simplified formalism for computing growth rates for perturbations within standard cosmology. We show that converting the perturbation evolution equations into ordinary differen1ia1 equations in terms of D-functions, related to the growth functions, not only simplifies fie equations, but also eliminates the commonly encountered complex problem of computing initial conditions in cosmological studies, avoiding making any assumptions - as is usually done - when setting up initial conditions for the perturbations.