Emergent Schrödinger Dynamics from Fisher Transport on the Null Sphere Bundle: Angular Reduction, Reversible Transport Completion, and the Quantum Action Scale
Eric Thompson
Abstract
In previous work, the master action of the null-directional kinematics (NDK) framework was constructed from Fisher-information transport on the sphere bundle over spacetime, yielding a real amplitude field $\psi(\hat{k};x)$ with a quadratic kinetic sector inherited from the information geometry of probability densities. This paper derives the emergent Schrödinger dynamics of that framework in a controlled low-energy limit. The derivation proceeds in four steps. First, a controlled angular reduction justified by the spectral gap of the sphere-bundle mode tower truncates the full field to a spacetime envelope $R(x)$ times a frozen angular profile. Second, the resulting reduced action is shown to be a real Fisher-density theory in spacetime. Third, the requirement that this density evolve locally and reversibly forces a canonically conjugate transport potential $S(x,t)$ via a continuity constraint. Fourth, the resulting $(\rho,S)$ system is shown to be exactly the Madelung form of a Schrödinger equation. The complex field is therefore not grafted onto the real theory but emerges as the compact packaging of a conjugate pair forced by reversible transport. Independent arguments from the dipole-current sector and the isotropic rest-mode sector pin the effective mass and the Fisher coefficient in terms of master-action couplings, yielding an emergent quantum scale of the form $\hbar_{\mathrm{eff}}^2 \sim 24\beta\Lambda_*/c^2$, with the precise numerical coefficient fixed up to order-unity convention-dependent factors. Stress-energy matching of the canonically normalized positive-frequency envelope fixes the density-normalization bridge at $n_*=1$. A systematic analysis then shows that all internal one-particle consistency conditions—free-particle dispersion, probability current, Galilean covariance, and circulation quantization—close without contradiction but do not generate an additional equation fixing the numerical value of $\hbar_{\mathrm{eff}}$. The program therefore derives the structure of quantum mechanics from the NDK directional substrate, while the absolute quantum action scale remains open and is isolated to a single product of master-action couplings.