  The quantum dynamics of a bulk-boundary theory is closely examined by the use
of the background field method. As an example we take the Mirabelli-Peskin
model, which is composed of 5D super Yang-Mills (bulk) and 4D Wess-Zumino
(boundary). Singular interaction terms play an important role of canceling the
divergences coming from the KK-mode sum. Some new regularization of the
momentum integral is proposed. An interesting background configuration of
scalar fields is found. It is a localized solution of the field equation. In
this process of the vacuum search, we present a new treatment of the vacuum
with respect to the extra coordinate. The "supersymmetric" effective potential
is obtained at the 1-loop full (w.r.t. the coupling) level. This is the
bulk-boundary generalization of the Coleman-Weinberg's case. Renormalization
group analysis is done where the correct 4d result is reproduced. The Casimir
energy is calculated and is compared with the case of the Kaluza-Klein model.
