First Constraints on a Pixelated Universe in Light of DESI

TL;DR

This paper investigates a string theory-inspired pixelated dark energy model, analyzing its compatibility with recent DESI data and finding it can fit or outperform the standard cosmological model in explaining dynamical dark energy.

Contribution

It provides the first cosmological analysis of the pixelated dark energy model, demonstrating its potential to fit observational data better than or comparable to ΛCDM.

Findings

The simplest pixelated model with constant growth rate fits the data marginally better than ΛCDM.

Models with increasing pixel growth rate could provide even better fits.

The analysis clarifies the UV features of dark energy needed to match observations.

Abstract

Pixelated dark energy is a string theory scenario with a quantum mechanically stable cosmological constant. The number of pixels that make up the universe slowly increases, manifesting as a time-dependent source of dark energy. DESI has recently reported evidence for dynamical dark energy that fits within this framework. In light of this, we perform the first cosmological analysis of the pixelated model. We find that the simplest model where the pixel growth rate is constant is able to accommodate the data, providing a marginally better fit than $\Lambda$CDM; and we show that models where the pixel growth rate is increasing and of order the Hubble constant today could provide better fits. Our analysis helps to clarify the features of UV constructions of dark energy necessary to accommodate the data.