Dirac oscillator in a self-gravitating cosmic string: confinement spectra beyond the conical approximation

Abstract

The gravitational field of a physical cosmic string is regular on the axis, curved across a finite vortex core, and only asymptotically conical. We test whether the bound-state spectrum of a transverse Dirac oscillator resolves this structure beyond the ideal-cone approximation. The fermion is treated as a test field on self-consistent Einstein--Abelian-Higgs vortex backgrounds, and the radial problem is cast as a generalized Hermitian eigenvalue problem. The numerical formulation is checked against the exact Minkowski and ideal-cone spectra and by independent shooting calculations. For a reference vortex family, the finite-core correction grows from the weak-confinement regime toward the percent level. When the normalized asymptotic cone is held fixed, the spectrum still varies with the measured Higgs-core radius, and the sampled backgrounds bracket a change of sign of the ground-state correction. The bound-state spectrum therefore contains information about the resolved core profiles that is not fixed by the asymptotic cone alone.