Speaker
Description
Although $\Lambda$CDM remains the standard cosmological model, outstanding observational and theoretical challenges motivate the exploration of alternative scenarios. Among these are models in which an anisotropic dark energy component breaks cosmic isotropy. In this talk, we investigate four classes of anisotropic dark energy models: a scalar field coupled to a vector field, a scalar field coupled to a 2-form field, scalar fields with an internal symmetry, and an inhomogeneous scalar field. We confront these models with background observations to constrain the present-day anisotropy of the cosmic expansion. Our results show that observations strongly favor the isotropic limit in all models except the scalar field coupled to a 2-form field, for which the isotropic limit is disfavored.