  Replacing the perturbative vacuum by the nonperturbative vacuum, we extend a
recent development of a quantum field theoretic framework for scalar and
pseudoscalar meson mixing. The unitary inequivalence of the Fock space of base
(unmixed) eigenstates and the physical mixed eigenstates is investigated and
the flavor vacuum state structure is explicitly found. This is exploited to
develop formulas for two flavor boson oscillations in systems of arbitrary
boson occupation number. We apply these formulas to analyze the mixing of eta
with eta' and comment on the other meson-mixing systems. In addition, we
consider the mixing of boson coherent states, which may have future
applications in the construction of meson lasers.
