  We elaborate on the topological order in the Kitaev chain, a p-wave
superconductor with nearest-neighbor pairing amplitude equal to the hopping
term Delta=t, and chemical potential mu=0. In particular, we write out the
explicit eigenstates of the open chain in terms of fermion operators, and show
that the states as well as their energy eigenvalues are formally equivalent to
those of an Ising chain. The models are physically different, as the
topological order in the Kitaev chain corresponds to conventional order in the
Ising model.
