  We analyze the Casimir effect for a flavor doublet of mixed scalar fields
con- fined inside a one-dimensional finite region. In the framework of the
unitary inequivalence between mass and flavor representations in quantum field
theory, we employ two alternative approaches to derive the Casimir force: in
the first case, the zero-point energy is evaluated for the vacuum of fields
with definite mass, then similar calculations are performed for the vacuum of
fields with defi- nite flavor. We find that signatures of mixing only appear in
the latter context, showing the result to be independent of the mixing
parameters in the former.
