SynchronoGeometry: A Geometric-Scalar Alternative to Dark Energy
Year: 2026
Type: article
Abstract: SynchronoGeometry: A Geometric‑Scalar Alternative to Dark Energy We present the SynchronoGeometry (SG) model, a geometric‑scalar framework that explains the late‑time cosmic acceleration without invoking a cosmological constant. The model introduces a non‑minimal coupling G(T,U,H) = ξ T² R between a scalar field T and the Ricci scalar R, together with an exponential potential V(T) = V₀ e^(−λT). We derive the background dynamics for a flat FRW universe and cast the field equations into an autonomous dynamical system. The analysis reveals a stable de Sitter attractor with w_eff = −1 and q < 0, naturally producing accelerated expansion. We constrain the model using a Markov Chain Monte Carlo (MCMC) analysis that combines:- Cosmic chronometer H(z) data (32 points),- Pantheon+SH0ES supernova distance modulus data (with full inverse covariance matrix). The median posterior values (with 68% credible intervals) are:ξ = 0.2477 (+0.1719, −0.1689),λ = 1.6262 (+0.2463, −0.2954),Ω_m0 = 0.1792 (+0.1566, −0.0866),V₀ = 3.6854 (+0.2524, −0.4177),H₀ = 65.01 (+2.79, −2.47) km/s/Mpc. Goodness‑of‑fit: χ²_min = 16.11, dof = 27, χ²/dof = 0.60, AIC = 26.11, BIC = 33.44. The model predicts a transition from deceleration to acceleration at z ~ 0.7, with w_eff(0) = −0.45 and q(0) = −0.20. This upload contains:- l2-8.pdf – Full manuscript.- l2.py, walker.py, walkera.py – Python codes for the SG model, MCMC, and plotting.- corner_Honly.png – Corner plot of posterior distributions.- Figure_1.png, Figure_2.png, Figure_3.png – Distance modulus, H(z), and w_eff/q plots.- H_z_fit.png – Best‑fit H(z) with data.- weff_q_Honly.png – w_eff(z) and q(z) curves.- Figure_4.jpg, Figure_5.jpg – Phase portraits in (x,u) and (x,y).- valid_points_with_V0_new.json – Initial guess data for MCMC. All files are provided to reproduce the results exactly. The work is licensed under Creative Commons Attribution 4.0 International. Cite as: Saadat Samadi Dinani, "SynchronoGeometry: A Geometric‑Scalar Alternative to Dark Energy", Zenodo, 2026. DOI: [reserved].
Author: Samadi, Saadat
Institution: Institute for Research in Fundamental Sciences
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7204454187
FWCI:
Cites:
Cited by:
Related to: