Anisotropic Inflation from Vector Impurity

TL;DR

This paper explores an anisotropic inflation model driven by a vector impurity, predicting observable effects such as primordial gravitational waves, even at low inflation scales.

Contribution

It introduces a new inflationary scenario with a vector impurity causing anisotropy and provides formulas to quantify this anisotropy.

Findings

Anisotropic inflation driven by vector impurity is feasible.

Primordial gravitational waves can be generated from curvature perturbations.

Observable signatures may include anisotropic patterns and gravitational waves.

Abstract

We study an inflationary scenario with a vector impurity. We show that the universe undergoes anisotropic inflationary expansion due to a preferred direction determined by the vector. Using the slow-roll approximation, we find a formula to determine anisotropy of the inflationary universe. We discuss possible observable predictions of this scenario. In particular, it is stressed that primordial gravitational waves can be induced from curvature perturbations. Hence, even in low scale inflation, a sizable amount of primordial gravitational waves may be produced during inflation.