Hubble Parameter Evolution in the 4DEU Framework: No Need for Dark Energy and Implications for the Hubble Tension

This is the final, peer-reviewed version of the paper published in Journal of High Energy Physics, Gravitation and Cosmology (Vol. 11, No. 4, 2025, pp. 1499–1515; DOI: 10.4236/jhepgc.2025.114092). https://doi.org/10.4236/jhepgc.2025.114092 The study demonstrates that the observed late-time acceleration of cosmic expansion can be fully explained within the Four-Dimensional Electromagnetic Universe (4DEU) framework—without invoking any dark energy component or modification of General Relativity.In this model, the Universe is a real four-dimensional hypersphere expanding uniformly at rate c along a privileged radial coordinate T. The apparent acceleration inferred from the redshift evolution of the Hubble parameter H(z) emerges as a geometric projection effect of this uniform 4D expansion onto its 3D hyperspherical section, where all observations take place. Using a model-independent compilation of cosmic-chronometer and Type Ia supernova data, the linear 4DEU prediction H(z)= H₀(1+z) was tested for two reference values of the Hubble constant.The statistical comparison shows a much stronger agreement with observations for the Planck-CMB value (H₀ ≈ 67 km s⁻¹ Mpc⁻¹) than for the local SH0ES value (H₀ ≈ 73 km s⁻¹ Mpc⁻¹), with a likelihood ratio of about 219:1 in favor of the former.This indicates that the so-called Hubble tension is naturally resolved within 4DEU as a projection effect, not as evidence for dark energy. This definitive version includes the full derivation of Equation (1), the global statistical analysis, and an expanded discussion comparing 4DEU with dark-energy and extended-gravity models.Overall, the results provide a purely geometric explanation of cosmic acceleration, fully consistent with observational data and achieved without introducing new fields, parameters, or exotic energy components.