M. Bordag et K. Kirsten, Ground state energy of a spinor field in the background of a finite radiusflux tube - art. no. 105019, PHYS REV D, 6010(10), 1999, pp. 5019
We develop a formalism for the calculation of the ground state energy of a
spinor field in the background of a cylindrically symmetric magnetic field.
The energy is expressed in terms of the Jost function of the associated sc
attering problem. Uniform asymptotic expansions needed are obtained from th
e Lippmann-Schwinger equation. The general results derived are applied to t
he background of a finite radius flux tube with a homogeneous magnetic fiel
d inside and the ground state energy is calculated numerically as a functio
n of the radius and the flux. It turns out to be negative, remaining smalle
r by a factor of alpha than the classical energy of the background except f
or very small values of the radius which are outside the range of applicabi
lity of QED. [S0556-2821(99)07118-0].