Entanglement of bosonic modes of material oscillators is studied in the
context of two bilinearly coupled, nonlinear oscillators. These oscillators are
realizable in the vibrational-cum-bending motions of C-H bonds in
dihalomethanes. The bilinear coupling gives rise to invariant subspaces in the
Hilbert space of the two oscillators. The number of separable states in any
invariant subspace is one more than the dimension of the space. The dynamics of
the oscillators when the initial state belongs to an invariant subspace is
studied. In particular, the dynamics of the system when the initial state is
such that the total energy is concentrated in one of the modes is studied and
compared with the evolution of the system when the initial state is such
wherein the modes share the total energy. The dynamics of quantities such as
entropy, mean of number of quanta in the two modes and variances in the
quadratures of the two modes are studied. Possibility of generating maximally
entangled states is indicated.Comment: 21 pages, 6 figure