Non-Gaussianity in three fluid curvaton model

TL;DR

This paper investigates non-Gaussianity in a three fluid curvaton model using second order perturbation theory, deriving formulas for temperature fluctuations and $f_{NL}$, and finds that non-Gaussianity is generally small and decreases with more adiabatic final states.

Contribution

It provides new general formulas for non-Gaussianity in a three fluid curvaton model, including non-adiabatic final states, extending previous adiabatic-only results.

Findings

Non-Gaussianity $|f_{NL}|$ is approximately 1.

Non-Gaussianity decreases as the system approaches an adiabatic final state.

Generated non-Gaussianity remains small in the studied scenario.

Abstract

The generation of non-gaussianity is studied in a three fluid curvaton model. By utilizing second order perturbation theory we derive general formulae for the large scale temperature fluctuation and non-gaussianity parameter, $f_{NL}$, that includes the possibility of a non-adiabatic final state. In the adiabatic limit we recover previously known results. The results are applied to a three fluid curvaton model where the curvaton decays into radiation and matter. We find that the amount of non-gaussianity decreases as the final state of the system becomes more adiabatic and that the generated non-gaussianity in the scenario is small, $|f_{NL}| \sim \mathcal{O}(1)$.