We present generalized Schiff's transformation on electric dipole moments
(EDM) in quantum field theory. By the unitary transformation, the time and
parity violating interaction i2ge​ψˉ​σμν​γ5​ψFμν is transformed into a new form, but its nonrelativistic
reduction has a unique form, which is free from Schiff's theorem. The
relativistic corrections to the new EDM operator turn out to be a small
increase to the EDM as given by b2​(αZ)2 with b2​≃2.
Therefore, the calculation of the EDM with nonrelativistic Hartree-Fock wave
functions presents the most conservative but reliable estimation for the
enhancement factor of the EDM in atoms.Comment: 23 pages, Prog. Theor. Phys. in pres