  Systems of neutral kaons can be used to observe entanglement and the
violation of Bell inequalities. The decay of these particles poses some
problems, however, and recently an effective formalism for treating such
systems has been derived. We generalize this formalism and make it applicable
to other quantum systems that can be made to behave in a similar manner. As
examples, we discuss two possible implementations of the generalized formalism
using trapped ions such as $^{171}$Yb or $^{172}$Yb, which may be used to
simulate kaonic behavior in a quantum optical system.
