# Dark energy and Dark matter interaction in light of the second law of thermodynamics

## TL;DR

This paper explores the thermodynamic basis for interactions between dark energy and dark matter, testing models with observational data, and finds evidence supporting energy transfer from dark energy to dark matter, with implications for cosmological models.

## Contribution

It introduces a thermodynamics-based framework to understand dark component interactions and tests specific models against observational data, revealing preferred energy flow directions.

## Key findings

- Evidence of interaction with energy flowing from dark energy to dark matter
- Best fit models suggest a phantom equation of state for dark energy
- Thermodynamics constraints influence the viability of interaction models

## Abstract

In the context of thermodynamics we discuss the way inevitable emerge an interaction between dark components, and in this way, provide a mechanism to understand the limits of the LCDM model and the class of interaction models between dark components. Using observational data we have tested two models of explicit interaction between dark components and reconstructed the evolution of temperatures for both components. We found that observations suggest the interaction exist with energy flowing from dark energy to dark matter. The best fit also suggest a phantom equation of state parameter for dark energy. We discuss the results having in mind the constraints imposed by thermodynamics.