What question did this study set out to answer?

The aim is to assess how accurate measurements of matter density influence dark energy evolution parameters.

March 24, 2026Open Access

Probing time-varying dark energy with DESI: the crucial role of precision matter density (₌ ₀) measurements

Key Points

The aim is to assess how accurate measurements of matter density influence dark energy evolution parameters.
Analyze sensitivities of cosmological observables (H(z), D_L(z), E_G) to matter density and dark energy parameters.
Use different parametrizations for dark energy to evaluate the effects on observables.
Quantify the sensitivity of H(z) and other observables to Ω_m0 and dark energy parameters.
Observables are more sensitive to Ω_m0 than to dark energy equation of state parameters.
At z ∼ 0.5, sensitivity of H(z) to Ω_m0 is approximately 0.7, while sensitivity to ω_a is around 0.04.
High-precision measurements of Ω_m0 are necessary to constrain time-varying dark energy.

Abstract

Abstract Accurate measurements of fundamental cosmological parameters, especially the Hubble constant (H₀ H 0) and present-day matter density (₌ ₀ Ω m 0), are crucial for constraining dark energy (DE) evolution. We analyze the sensitivities of cosmological observables (H (z), DL (z) D L (z), E ₆ E G) to ₌ ₀ Ω m 0, ₀ ω 0, and ₀ ω a under different parametrizations. Our results show observables are far more sensitive to ₌ ₀ Ω m 0 than to DE equation of state parameters (e. g. , at z 0. 5 z ∼ 0. 5, H (z) ’s ₌ ₀ Ω m 0 sensitivity is 0. 7 ∼ 0. 7 vs. ₀ ω a ’s 0. 04 ∼ 0. 04). This hierarchy mandates high-precision ₌ ₀ Ω m 0 measurements to accurately constrain time-varying DE. We also find DE parameter sensitivity highly depends on parametrization; the standard CPL form shows low sensitivity to ₀

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