Conventional physical theories separate the intrinsic connection between photons and tangible matter, and fail to clearly distinguish the physical functions of photon kinetic energy and momentum. Based on self-deduction and summarization of physical phenomena, this paper proposes a dual-state conversion model for free and bound photons. A free photon carries no rest mass, and all its energy exists as light kinetic energy, which generates secondary momentum via propagation at the speed of light. Once confined by external force fields and deprived of the condition to travel at light speed, the original light kinetic energy splits and solidifies: part of it converts into the rest mass of matter, and the residual energy turns into mechanical kinetic energy of substances, accompanied by the disappearance of corresponding photon momentum. This model clarifies the conceptual boundary between kinetic energy and momentum, establishes the conversion logic linking light, energy, mass and matter, and constructs a new theoretical system for mass-energy evolution and matter generation.
Jiaqing Yan (2026) studied this question.