DBI Lifshitz Inflation

TL;DR

This paper introduces a novel DBI inflation model where the inflaton moves in a Lifshitz throat with anisotropic scaling, leading to explicit covariance breaking after dimensional reduction.

Contribution

It develops a new DBI inflation framework with Lifshitz scaling and derives the perturbation action, connecting it to effective field theory classifications.

Findings

Derived the general perturbation action for the model.

Showed the explicit covariance breaking in the reduced theory.

Connected the model to effective field theory of inflation.

Abstract

A new model of DBI inflation is introduced where the mobile brane, the inflaton field, is moving relativistically inside a Lifshitz throat with an arbitrary anisotropic scaling exponent $z$. After dimensional reduction to four dimension the general covariance is broken explicitly both in the matter and the gravitational sectors. The general action for the metric and matter field perturbations are obtained and it is shown to be similar to the classifications made in the effective field theory of inflation literature.