Everpresent Lambda - II: Structural Stability

TL;DR

This paper investigates the stability of models with a fluctuating, time-dependent cosmological constant inspired by causal set theory, analyzing their sensitivity to initial assumptions and setup choices.

Contribution

It provides a detailed analysis of the structural stability of fluctuating dark energy models based on causal set theory, extending previous numerical simulations.

Findings

Models show sensitivity to initial conditions and parameter choices.

Fluctuating cosmological constant can produce stable dark energy behavior.

Insights into the robustness of causal set-inspired cosmological models.

Abstract

Ideas from causal set theory lead to a fluctuating, time dependent cosmological-constant of the right order of magnitude to match currently quoted "dark energy" values. Although such a term was predicted some time ago, a more detailed analysis of the resulting class of phenomenological models was begun only recently (based on numerical simulation of the cosmological equations with such a fluctuating term). In this paper we continue the investigation by studying the sensitivity of the scheme to some of the ad hoc choices made in setting it up.