Gibbs Energy Redistribution Theory (GERT): A Thermodynamically Motivated Expansion History and the Hubble Tension

Background: The standard cosmological model provides an excellent phenomenological description of the Universe. Motivated by persistent cosmological tensions, particularly in the Hubble constant (H0), this study proposes and tests the Gibbs Energy Redistribution Theory (GERT) as a thermodynamically grounded alternative to the expansion history model. Our central hypothesis is that a dynamical expansion history derived from fundamental thermodynamic principles empirically alleviates cosmological tensions, including the Hubble tension. At this stage, it provides a more physically coherent description of cosmic evolution, interpreting effects traditionally attributed to ad hoc dark components as emergent thermodynamic manifestations. Methods: We introduce a phenomenological, thermodynamically motivated model, the Gibbs Energy Redistribution Theory (GERT), in which the effective contributions of the matter- and lambda-like sectors are promoted to smooth, density-controlled functions, yielding a dynamical expansion history H(z) within the Friedmann Equation framework. We compared the resulting H(z) predictions with cosmic microwave background (CMB) shift-parameter constraints, baryon acoustic oscillation (BAO) distance measurements, and Type Ia supernova data. The analysis pipeline used standard open source scientific Python tools. Results: For the baseline implementation (the minimal-parameter reference fit described in the Methods), we obtained an excellent global fit (degrees of freedom (dof): χ2/dof ≈ 0.99) against CMB shift-parameter constraints, BAO distance measurements, and Type Ia supernova data, and inferred H0 ≈ 72.5 km s−1 Mpc−1, consistent with local determinations (e.g., SH0ES project). We quantified the deviations from the standard model in the diagnostic plots of H(z) and distance moduli. Conclusions: The framework yields concrete, testable predictions for late time expansion behavior, offering a physically coherent and causal narrative for cosmic evolution, and can be further constrained by future low-redshift probes.