Siavash Spacetime Dynamics (SSD): A Parameter-Free Geometric Framework Resolving the Hubble Tension and Cosmic Anomalies

Modern cosmology is currently facing a profound existential crisis characterized by systemic discrepancies between early-universe and late-universe observations. This paper introduces Siavash Spacetime Dynamics (SSD), a strictly parameter-free geometric framework that re- defines spacetime not as a static, inert background canvas, but as a dynamic, generative output of localized matter-energy interactions. By embedding a localized spacetime genera- tion rate (Ψ) directly into the Einstein Field Equations via a modified action principle, SSD preserves energy conservation while predicting continuous metric volume generation. The framework mathematically resolves the Hubble tension (yielding an exact 8.3% local expan- sion excess) and the σ8 anomaly, while offering an elegant, dark-matter-free mechanism for flat galactic rotation curves through geometric ambient pressure. License: This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0). You are free to share and adapt this material under the condition that appropriate credit is given to the original author, Siavash Sadeghi.