A Comprehensive Review of the First-Principle Unified Theory of Light Strings —— A New Physics Paradigm from the Unique Origin to Global Unification

This paper presents a comprehensive review and systematic introductory overview of the First-Principle Unified Theory of Light Strings. Over the past century, modern physics has achieved remarkable experimental accomplishments, yet it is deeply trapped in fragmentation at the fundamental level. Quantum mechanics and general relativity are mutually incompatible; the four fundamental forces lack a common origin; the essential nature of dark matter and dark energy remains unclear; and fundamental puzzles such as the origin of mass, the essence of electric charge, and the structure of spacetime remain unresolved. This work systematically reviews the First-Principle Unified Theory of Light Strings. Taking the "light string" as the sole fundamental physical entity of the universe, it constructs a globally unified foundational physics system with no additional assumptions, self-consistent logic, complete causality, and experimental verifiability, based on the underlying mechanisms of light string vibration, frequency coupling, phase coherence, closed-loop structure, and density gradient potential difference of the light string field. The theory has accomplished core breakthroughs: realizing the underlying unification of quantum mechanics and general relativity, interpreting the homologous mechanism of the four fundamental forces, strictly deriving the origin of particle mass and the quantitative mass-frequency relationship, revealing the physical essence of the gravitational constant G and the cosmological constant Λ, thoroughly resolving the baryon asymmetry problem and the black hole information paradox, providing a unified explanation for 66 classic unsolved experimental phenomena across disciplines, and proposing seven falsifiable decisive physical predictions. This paper serves as a systematic introductory overview of the whole theoretical system, clarifying the core framework, research scope, and fundamental physical problems that the First-Principle Unified Theory of Light Strings intends to solve.