Topological order in two-dimensional fermion systems with $p_x+ip_y$ pairing

We numerically evaluate the ``entanglement spectrum'' (singular value decomposition of the density matrix) of paired states of fermions in two dimensions that break parity and time-reversal symmetries, focusing on the spinless $p_x+ip_y$ case in which the gap function has orbital angular momentum $\ell=1$. In the weak-pairing phase, the low-lying entanglement spectrum has a gapless structure, which we compare to that of the Moore-Read state, a nonabelian quantum hall fluid. In the strong-pairing phase, we find a different structure, which we compare to the $\ell=0$, $s$-wave case. At the weak-strong transition, we compute the entanglement entropy from the spectrum, and find a logarithmic correction to the generic, ``area'' law behavior.