### Theoretical Cosmology

### — the study of universe and unknown quantities with mathematical tools.

##### Local Dynamics of Cosmological Scalar Field

##### Theoretical Cosmology - Computational Physics - Modified Gravity

AAS April Meeting 2020 (General oral session T15.8); Bettoni et al. (in prep)

(Click to play the presentation video)

"When analyzing theories in which dark energy is produced by a scalar field, it is usual to assume that the time variation of the scalar field in the Solar System is the same as the global, cosmological value. We test this hypothesis on a simple class of disformally coupled scalar-tensor theories by numerically evolving the scalar field around a spherical matter distribution. A non-negligible disformal coupling significantly affects the relationship between the local (within the dense region) and global (asymptotically) regimes. The observed contrast in the local and global behavior suggests the need to revise usual assumptions about the evolution of scalar fields, as well as the constraints derived using those assumptions."