# Interacting dark energy in the early 2020s: a promising solution to the $H_0$ and cosmic shear tensions

## TL;DR

This paper investigates a dark matter-dark energy interaction model that, when tested against recent cosmological data, alleviates the H_0 and cosmic shear tensions, suggesting a promising unified solution.

## Contribution

It introduces and tests a specific dark sector interaction model with current observational data, demonstrating its potential to resolve major cosmological tensions.

## Key findings

- Reduces H_0 tension to statistically plausible levels.
- Significantly alleviates the sigma_8 tension.
- Supports dark sector interactions as a viable solution.

## Abstract

We examine interactions between dark matter and dark energy in light of the latest cosmological observations, focusing on a specific model with coupling proportional to the dark energy density. Our data includes Cosmic Microwave Background (CMB) measurements from the Planck 2018 legacy data release, late-time measurements of the expansion history from Baryon Acoustic Oscillations (BAO) and Supernovae Type Ia (SNeIa), galaxy clustering and cosmic shear measurements from the Dark Energy Survey Year 1 results, and the 2019 local distance ladder measurement of the Hubble constant $H_0$ from the Hubble Space Telescope. Considering Planck data both in combination with BAO or SNeIa data reduces the $H_0$ tension to a level which could possibly be compatible with a statistical fluctuation. The very same model also significantly reduces the $\Omega_{\rm m}-\sigma_8$ tension between CMB and cosmic shear measurements. Interactions between the dark sectors of our Universe remain therefore a promising joint solution to these persisting cosmological tensions.