Boundary effects in quantum field theory
Abstract
Electromagnetic and scalar fields are quantized in the region near an arbitrary smooth boundary, and the renormalized expectation value of the stressenergy tensor is calculated. The energy density is found to diverge as the boundary is approached. For nonconformally invariant fields it varies, to leading order, as the inverse fourth power of the distance from the boundary. For conformally invariant fields the coefficient of this leading term is zero, and the energy density varies as the inverse cube of the distance. An asymptotic series for the renormalized stressenergy tensor is developed as far as the inversesquare term in powers of the distance. Some criticisms are made of the usual approach to this problem, which is via the "renormalized mode sum energy," a quantity which is generically infinite. Green'sfunction methods are used in explicit calculations, and an iterative scheme is set up to generate asymptotic series for Green's functions near a smooth boundary. Contact is made with the theory of the asymptotic distribution of eigenvalues of the Laplacian operator. The method is extended to nonflat spacetimes and to an example with a nonsmooth boundary.
 Publication:

Physical Review D
 Pub Date:
 December 1979
 DOI:
 10.1103/PhysRevD.20.3063
 Bibcode:
 1979PhRvD..20.3063D