Beta-function formalism for k-essence constant-roll inflation

Publication date: Available online 24 February 2020Source: Physics of the Dark UniverseAuthor(s): Abolhassan Mohammadi, Tayeb Golanbari, Khaled SaaidiAbstractThe beta-function formalism is being used to study the constant-roll inflation in k-essence models. Assuming the second slow-roll parameter as a constant leads to a first-order differential equation for β-function which much easier to solve and find a solution than the second (non-linear) order equation that we have in the corresponding standard constant-roll inflation. Many cosmological models are known as a subclass of k-essence, so we will try to consider the model as general as possible. It is determined that the second slow-roll parameter should be positive to produce a small value for the first slow-roll parameter. The scenario is considered for three well-known cosmological models, and it is clarified that for the non-canonical and tachyon model, the scalar spectral index never reaches the observational range, however for the DBI model we could arrive as a result consistent with the observational data.

Source: Physics of the Dark Universe - February 24, 2020 Category: Physics Source Type: research