  A nonzero electric dipole moment (EDM) of the neutron, proton, deuteron or
helion, in fact, of any finite system necessarily involves the breaking of a
symmetry, either by the presence of external fields (i.e. electric fields
leading to the case of induced EDMs) or explicitly by the breaking of the
discrete parity and time-reflection symmetries in the case of permanent EDMs.
We discuss two theorems describing these phenomena and report about the
cosmological motivation for an existence of CP breaking beyond what is
generated by the Kobayashi-Maskawa mechanism in the Standard Model and what
this might imply for the permanent electric dipole moments of the nucleon and
light nuclei by estimating a window of opportunity for physics beyond what is
currently known. Recent - and in the case of the deuteron even unpublished -
results for the relevant matrix elements of nuclear EDM operators are presented
and the relevance for disentangling underlying New Physics sources are
discussed.
