Non-relativistic limit of Dirac Hamiltonians with Aharonov-Bohm fields
Matteo Gallone, Alessandro Michelangeli, Diego Noja
TL;DR
The paper characterizes all self-adjoint realizations of Dirac- and Schrödinger-Aharonov-Bohm operators in two dimensions using Krein-Vishik-Birman-Grubb theory, revealing a block-wise structure by angular momentum. It then establishes a precise non-relativistic limit: after subtracting the rest energy and rescaling boundary data with $c$, the Dirac-AB family $H_ extα^{( extγ)}$ converges in norm-resolvent sense to a Schrödinger-AB family $S_ extα^{( extθ)}$, provided the extension parameters scale so that $rac{2m c}{1+2 extα} ext γ(c) o ext θ$. This yields a clean mapping from the full relativistic operator family to the physically relevant $s$-wave, angular-momentum commuting non-relativistic AB operators with relativistic approximants, clarifying both squared operators and the role of boundary conditions. The results give explicit resolvent formulas and illuminate how scattering length is preserved along the limit, with complementary discussion of the positron sector and exceptional cases.$
Abstract
We characterise the families of self-adjoint Dirac and Schrödinger operators with Aharonov-Bohm magnetic field, and we exploit the non-relativistic limit of infinite light speed to connect the former to the latter. The limit consists of the customary removal of the rest energy and of a suitable scaling, with the light speed, of the short-scale boundary condition of self-adjointness. This ensures that the scattering length of the Aharonov-Bohm interaction is preserved along the limit. Noteworthy is the fact that the whole family of Dirac-AB operators is mapped, in the non-relativistic limit, into the physically relevant sub-family of $s$-wave, angular-momentum-commuting, Schrö\-dinger-AB Hamiltonians with relativistic Dirac approximants.
