Determine the nature of dark energy

Determine the physical nature of dark energy, modeled as the cosmological constant Λ and described as a uniformly distributed energy component responsible for the accelerated expansion of the universe within the ΛCDM framework.

Background

The ΛCDM model includes dark energy, represented by the cosmological constant Λ, to account for the observed accelerated expansion of the universe. While its gravitational effect is well established, the underlying physical nature of dark energy is not known.

The authors note this uncertainty explicitly, distinguishing dark energy from dark matter and highlighting that its characterization remains a major open question in cosmology.

References

The Greek letter Λ (lambda) symbolizes a component of the model called cosmological constant, which manifests itself as a form of energy that uniformly fills the entire universe. Due to the unknown nature of this energy, it is also called dark energy.

— Illuminating dark matter I: A guide for physics teachers  (2406.15356 - Pinochet, 2024) in Footnote to Section 1 (Introduction)

However, observational evidence indicates that the universe is dominated by a dark energy component responsible for the accelerated expansion of the cosmos, whose nature remains an open question, motivating the analysis of its effects on black hole geometries.

— Exact solution of the Klein-Gordon equation in a Kiselev black hole background  (2609.04467 - Oliveira et al., 3 Sep 2026) in Introduction