What does this research mean for the field?

The Hubble tension can be explained as two measurements on opposite sides of the Péclet number Pe=1 regime boundary, rather than as a measurement error or new physics. Novelty: ClaimNovelty.NOVEL_FINDING. Consensus alignment: ConsensusAlignment.CHALLENGES_CONSENSUS.

What question did this study set out to answer?

This research aims to derive the cosmological Péclet number and relate it to the Hubble tension.

March 1, 2026Open Access

The Hubble Tension as a Péclet Regime Boundary: Drift-Diffusion Cosmology and the Pe=1 Crossing

Key Points

This research aims to derive the cosmological Péclet number and relate it to the Hubble tension.
Derived the Péclet number from the Friedmann acceleration equation
Analyzed the conditions for Pe_Λ=1
Explored implications for cosmic deceleration and acceleration
Identified Pe_Λ=1 as coinciding with the transition at z≈0.633
Explained Hubble tension as measurements on distinct sides of the Pe=1 regime
Predicted the discrepancy in measurement values from first principles.

Abstract

Derives the cosmological Péclet number Pe_Λ = Λc⁴/4πG (ρc²+3p) from the Friedmann acceleration equation and shows that Pe_Λ=1 is term-for-term identical to the cosmic deceleration-acceleration transition (z≈0. 633). The Hubble tension — H₀=67. 4 from CMB vs H₀=73. 0 from the distance ladder — is explained as two measurements on opposite sides of this Pe=1 regime boundary, not a measurement error or new physics. The sign, location, and order of magnitude of the discrepancy are predicted from first principles.

The Hubble Tension as a Péclet Regime Boundary: Drift-Diffusion Cosmology and the Pe=1 Crossing

Key Points

Abstract

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