Scalar and vector modes in inflation with antisymmetric tensor field

TL;DR

This paper studies the behavior and stability of scalar and vector perturbation modes in an inflationary model driven by an antisymmetric tensor field, focusing on potential instabilities and mode evolution.

Contribution

It provides a detailed analysis of scalar and vector mode stability and evolution in an antisymmetric tensor field-driven inflationary scenario, a novel approach in cosmological perturbation theory.

Findings

Identified four scalar and six vector modes relevant to the model.

Analyzed stability, finding conditions to avoid ghost and gradient instabilities.

Explored mode evolution across subhorizon and superhorizon scales.

Abstract

We investigate the scalar and vector modes arising from cosmological perturbations within the framework of an inflationary scenario driven by an antisymmetric tensor field, minimally coupled to gravity. After eliminating gauge artifacts, there remain four scalar and six vector modes of interest which can be studied separately. We analyze the stability of these modes, while looking for generic instabilities like ghost and gradient instabilities that could potentially plague the theory. Further, we investigate the evolution of these modes across different regimes, particularly subhorizon and superhorizon scales.