Constraining Entropic Cosmology

TL;DR

This paper explores how entropic gravity modifications influence cosmology, showing UV corrections can drive inflation, IR terms can produce dark energy, and observational data constrains these models, aligning with late-time acceleration and structure formation.

Contribution

It introduces new entropic cosmology models with quantum and surface term corrections, analyzing their observational viability and implications for inflation and dark energy.

Findings

UV entropic terms can induce inflation.

IR entropic corrections can explain dark energy.

Models are consistent with supernova, BAO, and CMB data.

Abstract

It has been recently proposed that the interpretation of gravity as an emergent, entropic force might have nontrivial implications to cosmology. Here two approaches are investigated: in one, the Friedman equation receives entropic contributions from the usually neglected surface terms, and in another, the extra terms are derived from quantum corrections to the entropy formula. UV terms may drive inflation, avoiding a recently derived no-go theorem, though in some cases leading to a graceful exit problem. IR terms can generate dark energy, alleviating the cosmological constant problem. The quantum corrections are bounded by their implications to the BBN, and the surface terms are constrained in addition by their effect upon the behavior of matter. Likelihood analyses are performed to constrain the modifications by the SNeIa, BAO and CMB data. It is found that a monomial correction to the area-entropy formula results in late acceleration in very good agreement with observations, which then turn out to be compatible with positive curvature. The evolution of perturbations is deduced by assuming the Jebsen-Birkhoff theorem. Distinct signatures can then be identified in the large scale structure formation. Furthermore, it is shown that the visible universe satisfies the Bekenstein bound.