# Cosmological Dynamics and Double Screening of DBI Galileon Gravity

## TL;DR

This paper explores the cosmological evolution and screening mechanisms of the DBI Galileon gravity model, revealing stable de Sitter solutions and a hybrid screening process influenced by source mass.

## Contribution

It introduces a detailed analysis of the cosmological dynamics and screening mechanisms in the DBI Galileon model, including the novel mixing of Vainshtein and DBIonic screening.

## Key findings

- De Sitter solutions and late-time acceleration without potential.
- Stable evolution free of ghost and Laplacian instabilities.
- Hybrid screening mechanism depending on source mass.

## Abstract

We investigate cosmological dynamics and screening mechanism of the Dirac-Born-Infeld (DBI) Galileon model. The model has been divided into two regimes, one has positive signs in front of scalar field kinetic terms so-called the DBI galileon, another one has negative signs and it is dubbed as the DBIonic galileon. We find de Sitter solution and evolution of the Universe starting from radiation dominated era to late-time accelerated expansion in the DBI galileon model without the presence of potential term. In one of the attractors, the ghost and Laplacian instabilities vanishes for the whole evolution. We find mixing of screening mechanisms between the Vainshtein mechanism and the DBIonic screening mechanism in the DBIonic galileon model, in which a scale changing between these two mechanisms depends on a mass of a source.