A Unified Theory of Fundamental Interactions Based on Energy Density and Field Gradient

Starting from the spatial distribution of energy density and field gradients, this paper establishes a fundamental physical framework that can uniformly explain the four fundamental interactions in nature. Strong force, weak force, electromagnetic force and gravity all originate from the spatial gradient change of energy density, and all satisfy the unified law of attenuation with the square of the spherical radius. Their differences are only determined by the spatial scale of energy confinement and the polarization structure. The strong and weak forces correspond to short-range confinement with extremely high energy density inside microscopic particles, while electromagnetic and gravitational forces correspond to long-range field energy gradients in external space. The dipolarization of electric charge and the tripolarization of color charge determine the coupling and transformation forms of interactions. Mass, having no polarization property, can only be linearly superposed. Photons form dipolar electrons and tripolar protons through different energy scales, and each transformation process independently satisfies energy conservation. This system realizes a unified description from light to matter and from microscopic structure to macroscopic field effects.