Anisotropic constant-roll inflation for the Dirac-Born-Infeld model

TL;DR

This paper explores anisotropic inflation in a string-inspired Dirac-Born-Infeld model, demonstrating exact solutions and their stability, challenging the cosmic no-hair conjecture with numerical verification.

Contribution

It introduces exact anisotropic inflationary solutions for a Dirac-Born-Infeld model under constant-roll conditions, extending supergravity-inspired models with novel coupling features.

Findings

Exact anisotropic inflationary solutions found

Solutions are numerically verified as attractors

Challenges the cosmic no-hair conjecture

Abstract

In this paper, we study a non-canonical extension of a supergravity-motivated model acting as a vivid counterexample to the cosmic no-hair conjecture due to its unusual coupling between scalar and electromagnetic fields. In particular, a canonical scalar field is replaced by the string-inspired Dirac-Born-Infeld one in this extension. As a result, exact anisotropic inflationary solutions for this Dirac-Born-Infeld model are figured out under a constant-roll condition. Furthermore, numerical calculations are performed to verify that these anisotropic constant-roll solutions are indeed attractive during their inflationary phase.