  We analyze the classical and quantum properties of the integrable dimer
problem. The classical version exhibits exactly one bifurcation in phase space,
which gives birth to permutational symmetry broken trajectories and a
separatrix. The quantum analysis yields all tunneling rates (splittings) in
leading order of perturbation. In the semiclassical regime the eigenvalue
spectrum obtained by numerically exact diagonalization allows to conclude about
the presence of a separatrix and a bifurcation in the corresponding classical
model.
