2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/50728Effects of the configuration of an external static magnetic field in the form of a singular vortex on the vacuum of a quantized massless spinor field are studied. The most general boundary conditions at the punctured singular point which make the twodimensional Dirac Hamiltonian to be self-adjoint are employed.10 pages, LateX, to be published in Proceedings of the International Conference "Quantization, Gauge Theory, and Strings" dedicated to the memory of Professor Efim Fradkin (June 5-10, 2000, Moscow, Russia)High Energy Physics - Theorytext