The n-wave procedure and dimensional regularization for the scalar field   in a homogeneous isotropic space
  We obtain expressions for the vacuum expectations of the energy-momentum tensor of the scalar field with an arbitrary coupling to the curvature in an N-dimensional homogeneous isotropic space for the vacuum determined by diagonalization of the Hamiltonian. We generalize the n-wave procedure to N-dimensional homogeneous isotropic space-time. Using the dimensional regularization, we investigate the geometric structure of the terms subtracted from the vacuum energy-momentum tensor in accordance with the n-wave procedure. We show that the geometric structures of the first three subtractions in the n-wave procedure and in the effective action method coincide. We show that all the subtractions in the n-wave procedure in a four- and five-dimensional homogeneous isotropic spaces correspond to a renormalization of the coupling constants of the bare gravitational Lagrangian. 
Yu. V. Pavlov