  Spin-orbit coupled superconductors are potentially interesting candidates for
realizing topological and potentially non-Abelian states with Majorana
Fermions. We argue that time-reversal broken spin-orbit coupled superconductors
generically can be characterized as having sub-gap states that are bound to
localized non-magnetic impurities. Such bound states, which are referred to as
Shiba states, can be detected as sharp resonances in the tunneling spectrum of
the spin-orbit coupled superconductors. The Shiba state resonance can be tuned
using a gate-voltage or a magnetic field from being at the edge of the gap at
zero magnetic fields to crossing zero energy when the Zeeman splitting is tuned
into the topological superconducting regime. The zero-crossing signifies a
Fermion parity changing first order quantum phase transition, which is
characterized by a Pfaffian topological invariant.
  These zero-crossings of the impurity level can be used to locally
characterize the topological superconducting state from tunneling experiments.
