We classify entanglement singularities for various two-mode bosonic systems
in terms of catastrophe theory. Employing an abstract phase-space
representation, we obtain exact results in limiting cases for the entropy in
cusp, butterfly, and two-dimensional catastrophes. We furthermore use numerical
results to extract the scaling of the entropy with the non-linearity parameter,
and discuss the role of mixing entropies in more complex systems.Comment: 7 pages, 3 figure
