Enhancing Inflationary Tensor Modes through Spectator Fields

TL;DR

This paper demonstrates that spectator scalar fields with subluminal sound speeds can significantly enhance tensor modes during inflation, providing a novel mechanism for generating observable gravitational waves.

Contribution

It introduces a new approach where spectator fields with low sound speed amplify inflationary tensor modes, expanding the theoretical landscape.

Findings

Spectator fields with low sound speed increase tensor mode amplitude.

The mechanism can produce observable gravitational waves.

The model offers new insights into inflationary tensor mode generation.

Abstract

We show that a large contribution to tensor modes during inflation can be generated by a spectator scalar field with speed of sound lower than unity.