Physical Propagation as Spectral Dynamics of Unitary Operators Foundations of a spectral description of propagation
Jonatan P. camargo
Abstract
We present a structural formulation of physical dynamics based on discrete unitary propagation, in which the time evolution is directly described by a unitary operator $\hat W=f(\hat H)$ associated with a self-adjoint structural operator $\hat H$. Starting from the relationship between action and phase, $\phi=S/\hbar$, and the variational construction of structural operators, we show that the propagation can be written exactly as the action of a bilocal kernel $W(x,y)$ on the state, in continuity with recent developments of the Action-Phase program. We show that the spectral decomposition of $\hat H$ induces a diagonalization of the unitary propagation, in which the state evolution becomes multiplicative in the eigenvector basis of the structural operator. Consequently, the spectral structure organizes the propagation modes of the system, providing a description in which the dynamics is expressed in a decoupled manner between modes. It is evidenced that the distinction between nodal representation and spectral representation emerges naturally from the operator structure, corresponding to different decompositions of the same state in distinct bases of the same Hilbert space. In the case of translational invariance, the decomposition into Fourier modes is recovered as a particular situation. The results presented do not constitute a complete reconstruction of quantum mechanics nor a general gravitational theory. In particular, aspects of measurement, multiparticle structures, or complete covariant formulations are not treated. The objective of this work is more restricted and precise: to establish a formulation in which the dynamics is determined by the propagation operator and organized by its spectral decomposition, providing a structural layer from which more complete physical descriptions can be developed.