From UD Theory to Quantum Mechanics: The Spinor Projection and the Rigorous Emergence of Quantum Postulates
Dan Zhu
Abstract
We derive the foundational postulates of quantum mechanics from the UD axioms. Starting from the four-aspect field structure, we construct the spinor projection $\psi = (U_u + iU_d,\; D_d + iD_u)^{\mathsf{T}}$. The $U(1)$ Noether current from the Dirac action gives the conserved probability density, and the global normalization axiom yields the Born rule. The $D_u$ field (U in matter) is continuous and linear, explaining wave-like phenomena such as interference. The $D_d$ field (D in matter) is localized and determinate, explaining particle-like behavior and the absence of macroscopic superpositions. The measurement process is described by a coupling Hamiltonian derived from the UD interaction, which entangles the $D_u$ field with a macroscopic $D_d$ apparatus, leading to dissipation of $D_u$ coherence and the Born rule without collapse. The $U\leftrightarrow D$ duality implies the existence of antiparticles with opposite phase. All derivations are self-contained and logically inevitable.