Fluid Inflation

TL;DR

This paper introduces a fluid-based inflationary model using a perfect barotropic fluid, demonstrating how it produces a non-attractor inflationary universe with a scale-invariant power spectrum and specific non-Gaussianity features.

Contribution

It presents a novel inflationary mechanism based on fluid dynamics, detailing the calculation of power spectrum and bispectrum for a perfect fluid, and highlights the non-attractor nature of this inflation model.

Findings

Produces a scale-invariant power spectrum

Shows non-attractor inflationary behavior

Finds local non-Gaussianity parameter f_NL= 5/2

Abstract

In this work we present an inflationary mechanism based on fluid dynamics. Starting with the action for a single barotropic perfect fluid, we outline the procedure to calculate the power spectrum and the bispectrum of the curvature perturbation. It is shown that a perfect barotropic fluid naturally gives rise to a non-attractor inflationary universe in which the curvature perturbation is not frozen on super-horizon scales. We show that a scale-invariant power spectrum can be obtained with the local non-Gaussianity parameter $f_{NL}= 5/2$.