Causal Entropy Bound for Non-Singular Cosmologies

TL;DR

This paper verifies the validity of the Causal Entropy Bound in non-singular cosmologies, showing it can effectively identify physically consistent models beyond traditional energy conditions.

Contribution

It demonstrates that the CEB's validity conditions are the same as previously established criteria and applies this to non-singular cosmologies for the first time.

Findings

CEB validity requires sub-Planckian, not too negative energy densities.

CEB can distinguish physically consistent non-singular cosmologies.

CEB is more reliable than traditional energy conditions in some cases.

Abstract

The conditions for validity of the Causal Entropy Bound (CEB) are verified in the context of non-singular cosmologies with classical sources. It is shown that they are the same conditions that were previously found to guarantee validity of the CEB: the energy density of each dynamical component of the cosmic fluid needs to be sub-Planckian and not too negative, and its equation of state needs to be causal. In the examples we consider, the CEB is able to discriminate cosmologies which suffer from potential physical problems more reliably than the energy conditions appearing in singularity theorems.