  Both the nonrelativistic scattering and the spectrum in the presence of the
Aharonov-Bohm potential are analyzed. The single-particle density of states
(DOS) for different self-adjoint extensions is calculated. The DOS provides a
link between different physical quantities and is a natural starting point for
their calculation. The consequences of an asymmetry of the S matrix for the
generic self-adjoint extension are examined.
  I. Introduction
  II. Impenetrable flux tube and the density of states
  III. Penetrable flux tube and self-adjoint extensions
  IV. The S matrix and scattering cross sections
  V. The Krein-Friedel formula and the resonance
  VI. Regularization
  VII. The R --> 0 limit and the interpretation of self-adjoint extensions
  VIII. Energy calculations
  IX. The Hall effect in the dilute vortex limit
  X. Persistent current of free electrons in the plane pierced by a flux tube
  XI. The 2nd virial coefficient of nonrelativistic interacting anyons
  XII. Discussion of the results and open questions
