Atomic CP-violating polarizability

Searches for CP-violating effects in atoms and molecules provide important constrains on competing extensions to the standard model of elementary particles. In particular, CP violation in an atom leads to the CP-odd T,P-odd polarizability CP: a magnetic moment CP is induced by an electric field E0 applied to an atom, CP= E0. We estimate the CP-violating polarizability for rare-gas diamagnetic atoms He through Rn. We relate CP to the permanent electric dipole moment EDM of the electron and to the scalar constant of the CP-odd electron-nucleus interaction. The analysis is carried out using the third-order perturbation theory and the Dirac-Hartree-Fock formalism. We find that, as a function of nuclear charge Z , CP scales steeply as Z5R Z , where slowly varying R Z is a relativistic enhancement factor. Finally, we evaluate the feasibility of setting a limit on electron EDM by measuring CP-violating magnetization of liquid Xe. We find that such an experiment could provide competitive bounds on electron EDM only if the present level of experimental sensitivity to ultraweak magnetic fields Kominis et al., Nature 422, 596 2003 is improved by several orders of magnitude.