Quantised bulk fields in the Randall-Sundrum compactification model

The quantisation of a scalar field in the five-dimensional model suggested by Randall and Sundrum is considered. Using the Kaluza-Klein reduction of t he scalar field, discussed by Goldberger and Wise, we sum the infinite towe r of modes to find the vacuum energy density. Dimensional regularisation is used and we compute the pole term needed for renormalisation, as well as t he finite part of the energy density. Some comments are made concerning the possible self-consistent determination of the radius. (C) 2000 Elsevier Sc ience B.V. All rights reserved.