Control and manipulation of the angular momentum of optical, electronic, or light-matter interacting systems has given rise to a myriad of applications. Majority of these applications, however, deploy only global angular momentum properties of these fields by solely incorporating far-field interactions or the conservation of total angular momentum. Local properties of optical and electronic fields and their interactions in the near-field region have been gaining attention only recently and a thorough understanding of these dynamics is still essential.

Here we study the angular momentum dynamics of light-matter interacting systems from a fundamental relativistic point of view. By applying Noether’s theorem to the quantum electrodynamics Lagrangian, we discover a local conservation of angular momentum equation applicable to far-field and near-field interactions. In contrast to the widely used duality symmetry approach towards the local conservation of helicity, our approach is quantum, relativistic, applies to light-matter interactions, does not introduce a new gauge field, and thus is experimentally testable. Our theory not only applies to the recent near-field and local light-matter experiments, but it also pushes the frontiers in light-matter interactions for the realization of next generations of experiments on the role of angular momentum. We further investigate the light-matter interacting system of an atom or a quantum dot coupled to the evanescent fields of a spherical resonator. We show that, due to the local alignment of the optical spin of the resonant modes and the radiated field of the source, the modes of the resonator are excited asymmetrically depending on the Zeeman transitions of the source. These results show the importance of local and near-field photonic spin in realizing on-chip quantum routing of single photons in quantum optical networks. Our work presents a generalization of universal spin-momentum locking of light to 3D structures. Moreover, we take the Dirac-Maxwell correspondence approach–the study of similarities between the Dirac and Maxwell’s equations–by presenting the solutions of Dirac equation for a cylindrical geometry. Labeled as Dirac wire, this geometry is the electronic analogue of an optical fiber. We have presented a set of new solutions for three types of