Predicting the Cosmological Constant from the Causal Entropic Principle

TL;DR

This paper uses the Causal Entropic Principle to predict the cosmological constant, showing that entropy maximization in causally connected regions aligns well with observed values, emphasizing thermodynamics' role in cosmology.

Contribution

It introduces a novel application of the Causal Entropic Principle to predict the cosmological constant, linking entropy production to observed cosmological parameters.

Findings

Entropy production is maximized by dust heated by stars.

Predicted cosmological constant matches observational data.

Thermodynamic selection offers a compelling alternative to anthropic reasoning.

Abstract

We compute the expected value of the cosmological constant in our universe from the Causal Entropic Principle. Since observers must obey the laws of thermodynamics and causality, the principle asserts that physical parameters are most likely to be found in the range of values for which the total entropy production within a causally connected region is maximized. Despite the absence of more explicit anthropic criteria, the resulting probability distribution turns out to be in excellent agreement with observation. In particular, we find that dust heated by stars dominates the entropy production, demonstrating the remarkable power of this thermodynamic selection criterion. The alternative approach - weighting by the number of "observers per baryon" - is less well-defined, requires problematic assumptions about the nature of observers, and yet prefers values larger than present experimental bounds.