Work

The pseudo-complex FLRW model and the time evolution of the Hubble parameter

Year: 2026

Type: article

Abstract: The pseudo-complex version of the Friedmann–Lemaître–Robertson–Walker model (pcFLRW) is presented within the framework of pseudo-complex General Relativity (pcGR). In this approach, dark energy emerges as a geometric consequence of the pseudo-complex structure, leading to a specific functional form for the Hubble parameter H ( z ) characterized by a single geometric parameter $$\beta $$ β . This parameter governs the effective dark-energy equation of state via $$p_\Lambda = -\beta \varepsilon _\Lambda $$ p Λ = - β ε Λ and is directly linked to the present-day time derivative of the Hubble parameter through $$\dot{H}_0 = \frac{3}{2}(\beta -1)H_0^2$$ H ˙ 0 = 3 2 ( β - 1 ) H 0 2 . Using recent DESI BAO data, we constrain $$\beta = 1.0426 \pm 0.0144$$ β = 1.0426 ± 0.0144 , which yields a positive $$\dot{H}_0 \simeq (0.94 \pm 0.32)\times 10^{-17}\,\mathrm {(km/s^2)/Mpc}$$ H ˙ 0 ≃ ( 0.94 ± 0.32 ) × 10 - 17 ( km / s 2 ) / Mpc . This contrasts with the $$\Lambda $$ Λ CDM prediction, where $$\dot{H}_0$$ H ˙ 0 is negative ( $$\dot{H}_0 \approx -0.45 H_0^2$$ H ˙ 0 ≈ - 0.45 H 0 2 for standard parameters), indicating that in pcGR the expansion rate is increasing with time while in $$\Lambda $$ Λ CDM it decreases. The best-fit value also implies a deceleration parameter $$q = -0.9361 \pm 0.0216$$ q =

Source: The European Physical Journal C

DOI: 10.1140/epjc/s10052-026-15613-3

Authors: L. Maghlaoui, P. O. Hess, F. Weber, C. A. Zen Vasconcellos