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arXiv · 1912.07006

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

Abolhassan Mohammadi·Tayeb Golanbari·Khaled Saaidi
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Abstract

The beta function formalism is being used to study the constant-roll inflation in the k-essence model. Assuming the second slow-roll parameter as a constant leads to a first-order differential equation for $\beta$-function which is much easier to solve and find a solution than the second (non-linear) order equation that we have in 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 at a result consistent with observational data.

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Abolhassan Mohammadi, Tayeb Golanbari, Khaled Saaidi. 2019-12-15. Beta-function formalism for k-essence constant-roll inflation. https://doi.org/10.1016/j.dark.2020.100505

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