2026/08/03 by Ju Gao, Fang Shen
Physics and Astronomy · #quant-ph
5 pages, 2 figures
arxiv created 2026/08/03 · arxiv updated 2026/08/04
Free-space Aharonov--Bohm (AB) Bessel modes are known to carry a flux-dependent azimuthal Schrödinger probability current and kinetic orbital angular momentum. We extend this response to the spin-resolved conserved Dirac current of a core-excluded finite-wall annular guide and show that confinement converts its surviving orbital component into a transverse Aharonov--Bohm (TAB) propagation phase for a straight traveling mode whose centroid path has zero projection onto \mathbf A. The radial-gradient current reverses under spin reversal; retaining the complete evanescent tail closes it as a boundary contribution, leaving a spin-independent orbital phase Δϕln∝ lΦL\rm int⟨ρ-2⟩ln/vz. Opposite-winding modes |± l⟩ form a same-path qubit implementing Rz(2δl) with differential readout and common-mode phase rejection, while direct first-order crosstalk requires the angular harmonic m=±2l. For a 100 μm section with a=20 nm, R=30 nm, Ez=10 meV, and |l|=10, the sensitivity is 0.1885 mrad/mG and Rz(π) occurs at 16.67 G. Finite-wall confinement thus turns intrinsic azimuthal Dirac current into a guided field-free phase operation.