Viability of Big Bang Nucleosynthesis in Some Generalized Horizon Entropies

TL;DR

This study assesses whether certain cosmological models based on generalized horizon entropies are consistent with Big Bang Nucleosynthesis constraints, finding most models viable except for lithium predictions.

Contribution

It introduces a framework to test generalized horizon entropy models against BBN constraints, establishing their viability within early-Universe bounds.

Findings

Most models satisfy helium and deuterium abundance constraints.

The freeze-out temperature provides the strongest bounds on model parameters.

Lithium constraints are not satisfied, consistent with the known lithium problem.

Abstract

In this work, we investigate the viability of some cosmological models derived from generalized horizon entropies, using Big Bang Nucleosynthesis (BBN) constraints. By analyzing the deviations in the expansion rate, we derive bounds on the model parameters from freeze-out temperature, helium, and deuterium abundances. Our results show that the freeze-out condition provides the most stringent constraint, while helium and deuterium bounds remain consistent across all models. Although lithium constraints are not satisfied, this discrepancy is attributed to the well-known cosmological lithium problem. Furthermore, the parameter values required for late-time cosmic acceleration are found to lie well within the BBN bounds, demonstrating consistency between early- and late-Universe behavior. These results establish the viability of the considered models within the framework of BBN.