Anti-Anthropic Solutions to the Cosmic Coincidence Problem

TL;DR

This paper proposes anti-anthropic scalar field models as an alternative to the cosmological constant, addressing the cosmic coincidence problem and predicting distinct observational signatures for future experiments.

Contribution

It introduces tracking scalar field models that eliminate the need for fine-tuning and provide a different future evolution of the Universe compared to the cosmological constant.

Findings

Models remove the need for fine-tuning in dark energy explanations.

They predict transient scalar field energy periods with observable signatures.

These models can be tested with current and upcoming cosmological experiments.

Abstract

A cosmological constant fits all current dark energy data, but requires two extreme fine tunings, both of which are currently explained by anthropic arguments. Here we discuss anti-anthropic solutions to one of these problems: the cosmic coincidence problem- that today the dark energy density is nearly equal to the matter density. We replace the ensemble of Universes used in the anthropic solution with an ensemble of tracking scalar fields that do not require fine-tuning. This not only does away with the coincidence problem, but also allows for a Universe that has a very different future than the one currently predicted by a cosmological constant. These models also allow for transient periods of significant scalar field energy (SSFE) over the history of the Universe that can give very different observational signatures as compared with a cosmological constant, and so can be confirmed or disproved in current and upcoming experiments.