Schr\"{o}dinger equation is $\mathcal{R}$-separable in toroidal coordinates
Quantum Physics
2025-11-13 v1
Abstract
We present, for the first time, exact solutions for the Schr\"{o}dinger equation in Moon and Spencer's toroidal coordinates, and in the electromagnetic toroidal--poloidal coordinate systems. Curiously, both systems present a fractional angular momentum, because of the torus's hole. We achieve these novel solutions using the irregular -separation of variables, an unexplored approach in Physics, which results in a wavefunction with fractional angular momentum eigenvalues. Numerous solutions for the Schr\"{o}dinger equation in a variety of external potentials are shown, including an external magnetic field. A plane-wave expansion and a Green function are also presented, setting the stage for future progress in this area.
Cite
@article{arxiv.2511.08646,
title = {Schr\"{o}dinger equation is $\mathcal{R}$-separable in toroidal coordinates},
author = {Matheus E. Pereira and Alexandre G. M. Schmidt},
journal= {arXiv preprint arXiv:2511.08646},
year = {2025}
}