A generalized mass-to-horizon relation: a new global approach to entropic cosmologies and its connection to $\Lambda$CDM

TL;DR

This paper introduces a generalized mass-to-horizon relation in entropic cosmology, unifying various entropy forms and showing that for a specific parameter value, it reproduces the standard Lambda-CDM model, aligning well with observational data.

Contribution

It proposes a new generalized mass-to-horizon relation that unifies different entropic cosmologies and demonstrates its equivalence to Lambda-CDM for a specific parameter choice.

Findings

For n=3, the model is equivalent to Lambda-CDM.

Models with log gamma < -3 fit data as well as Lambda-CDM.

The new relation supports the thermodynamic consistency of entropic cosmologies.

Abstract

In this letter, we propose a new generalized mass-to-horizon relation to be used in the context of entropic cosmologies and holographic principle scenarios. We show that a general scaling of the mass with the Universe horizon as $M=\gamma \frac{c^2}{G}L^n$ leads to a new generalized entropy $S_n = \gamma \frac{n}{1+n}\frac{2 \pi\,k_B\,c^3}{G\,\hbar} L^{n+1}$ from which we can recover many of the recently proposed forms of entropies at cosmological and black hole scales and also establish a thermodynamically consistent relation between each of them and Hawking temperature. We analyse the consequences of introducing this new mass-to-horizon relation on cosmological scales by comparing the corresponding modified Friedmann, acceleration, and continuity equations to cosmological data. We find that when $n=3$, the entropic cosmology model is fully and totally equivalent to the standard $\Lambda$CDM model, thus providing a new fundamental support for the origin and the nature of the cosmological constant. In general, if $\log \gamma < -3$, and irrespective of the value of $n$, we find a very good agreement with the data comparable with $\Lambda$CDM from which, in Bayesian terms, our models are indistinguishable.