Functional determinants and Casimir energy in higher dimensional   spherically symmetric background potentials
  In this paper we analyze the spectral zeta function associated with a Laplace operator acting on scalar functions on an N-dimensional Euclidean space in the presence of a spherically symmetric background potential. The obtained analytic continuation of the spectral zeta function is then used to derive very simple results for the functional determinant of the operator and the Casimir energy of the scalar field. 
Guglielmo Fucci and Klaus Kirsten
hep-th math-ph math.MP