Work

Alleviating cosmological tensions with a hybrid dark sector

Year: 2025

Type: article

Abstract: We investigate a cosmological model inspired by hybrid inflation, where two scalar fields representing dark energy (DE) and dark matter (DM) interact through a coupling that is proportional to the DE scalar field 1 / ϕ . The strength of the coupling is governed solely by the initial condition of the scalar field, ϕ i , which parametrizes deviations from the standard Λ cold dark matter ( Λ CDM ) model. In this model, the scalar field tracks the behavior of DM during matter domination until it transitions to DE while the DM component decays quicker than standard CDM during matter domination, and is therefore different from some interacting DM-DE models which behave like phantom dark energy. Using 2018 CMB data, Dark Energy Spectroscopic Instrument baryonic acoustic oscillations measurements and Pantheon + supernova observations, we find that the model allows for an increase in H 0 that can help reduce the Hubble tension. In addition, we find that higher values of the coupling parameter are correlated with lower values of ω m , and a mild decrease of the weak-lensing parameter S 8 , potentially relevant to address the S 8 tension. Bayesian model comparison, however, reveals inconclusive results for most datasets, unless S H 0 ES data are included, in which case a moderate evidence in favor of the hybrid model is found.

Source: Physical review. D/Physical review. D.

DOI: 10.1103/9lf2-33zf

Authors: Elsa M. Teixeira, Gaspard Poulot, Carsten van de Bruck, Eleonora Di Valentino, Vivian Poulin

Institutions: Laboratoire Univers et Particules de Montpellier, University of Sheffield

Language: English

Topic: Cosmology and Gravitation Theories

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: hybrid