# de Sitter swampland bound in the Dirac-Born-Infeld inflation model

## TL;DR

This paper investigates the de Sitter swampland conjecture within the Dirac-Born-Infeld inflation model, deriving bounds on the potential's gradient and showing that quasi-de Sitter spacetime arises from tuning in this framework.

## Contribution

It derives the de Sitter swampland bound for the DBI inflation model using entropy and distance arguments, linking backreaction to the slow-roll parameter.

## Key findings

- Bounds on $m_{Pl}
abla V / V$ depending on warping and field range.
- Interpretation of backreaction as a natural bound for the slow-roll parameter.
- Quasi-dS spacetime in the DBI model requires tuning.

## Abstract

We study the de Sitter (dS) swampland conjecture in the Dirac-Born-Infeld (DBI) inflation model. We obtain the dS swampland bound for the relativistic regime using Bousso's entropy bound argument and proper distance. It restricts $m_{\rm Pl}\nabla V/V$ by some positive constant depending on warping and the field range. In the specific case of the DBI model driven by the quadratic potential, the model-dependent backreaction argument is interpreted as a natural bound for the slow-roll parameter. This shows that quasi-dS spacetime in the DBI model is a result of tuning.