Vacuum polarization of a scalar field in wormhole spacetimes
  An analitical approximation of $<\phi^2>$ for a scalar field in a static spherically symmetric wormhole spacetime is obtained. The scalar field is assumed to be both massive and massless, with an arbitrary coupling $\xi$ to the scalar curvature, and in a zero temperature vacuum state. 
Arkadii A. Popov, Sergey V. Sushkov