Warm non-minimally coupled Peccei–Quinn inflation and de Sitter Swampland conjecture

Abstract

In this study, we explore the dynamics of warm inflation within a non-minimally coupled Peccei–Quinn (PQ) framework and evaluate its compatibility with the de Sitter Swampland Conjecture. Our model incorporates a PQ scalar field that is non-minimally coupled to gravity, facilitating inflation through a dissipative process that sustains a thermal bath, thereby distinguishing it from conventional cold inflation. We analyze the dissipation coefficient defined as $\Gamma (T,\sigma )=C_n{T}^n{\sigma }^p{M}^{1-n-p}$, where $C_n$ is a dimensionless constant, M is a mass scale, and n and p are numerical powers. Our investigation focuses on three specific cases: (a) A temperature-dependent dissipation coefficient with an inverse relation, $\Gamma =C_{-1}{\sigma }^2/T$, where $n=-1$ and $p=2$; (b) A dissipation coefficient linear in field ϕ, $\Gamma =C_0\sigma$, where $n=0$ and $p=1$; and (c) A dissipation coefficient linear in temperature T, $\Gamma =C_{1}T$, where $n=1$ and $p=0$. By examining the slow-roll dynamics in these inflationary scenarios, we derive essential cosmological parameters, including the scalar spectral index and the tensor-to-scalar ratio. We compare our results with the latest observational data from Planck 2018. Our findings suggest that the model is consistent with observational constraints while simultaneously satisfying the de Sitter Swampland conditions.