Primordial non-Gaussianity in noncanonical warm inflation: Three- and four-point correlations

Abstract

Non-Gaussianity generated in inflation can be contributed by two parts. The first part, denoted by f δN NL , is the contribution from four-point correlation of inflaton field which can be calculated using δN formalism, and the second part, denoted by f int NL , is the contribution from the three-point correlation function of the inflaton field. We consider the two contributions to the non-Gaussianity in noncanonical warm inflation throughout (noncanonical warm inflation is a new inflationary model which is proposed in [18]). We find the two contributions are complementary to each other. The four-point correlation contribution to the non-Gaussianity is overwhelmed by the three-point one in strong noncanonical limit, while the conclusion is opposite in the canonical case. We also discuss the influence of the field redefinition, thermal dissipative effect and noncanonical effect to the non-Gaussianity in noncanonical warm inflation.

Warm brane inflation with an exponential potential: A consistent realization away from the swampland

“…[74], there has been other more recent analysis of non-Gaussianities in WI, for example the ones in Refs. [76,77], using for instance the δN formalism. However, the δN formalism probes better the non-Gaussianity of the local shape, while the warm shape of WI, valid in the strong dissipative regime, is very weakly correlated with the local shape [78].…”

Observational constraints on warm quasi-exponential inflation

“…However, as it has been suggested in Ref. [65], warm inflation driven by a non-canonical field may generate a larger amount of non-Gaussianities than the canonical case. We hope to be able to address that issue in a future work.…”