Intrinsic Electric Dipole Moments of Paramagnetic Atoms: Rubidium and Cesium

The electric dipole moment (EDM) of paramagnetic atoms is sensitive to the intrinsic EDM contribution from that of its constituent electrons and a scalar-pseudoscalar (S-PS) electron-nucleus interaction. The electron EDM and the S-PS contributions to the EDMs of these atoms scale as $\approx Z^3$. Thus, the heavy paramagnetic atoms will exhibit large EDM enhancement factors. However, the sizes of the couplings are so small that they are of interest of high precision atomic experiments. In this work we have computed the EDM enhancement factors of the ground states of Rb and Cs due to both the electron EDM and the S-PS EDM using the relativistic coupled-cluster theory. The importance of determining precise ab initio enhancement factors and experimental results of atomic EDMs in deducing a reliable limit on the electron EDM is emphasized.

Figure 1

The variation in the trends of the dominant RCC terms such as (a) $\overline{D^{(0)}}{S}_v^{(1)}$, (b) $\overline{D^{(0)}}{T}^{(1)}$, (c) $S_v^{(0{)}^{†}}\overline{D^{(0)}}{S}_v^{(1)}$, and (d) total $e$-EDM enhancement factor ($R$) with the size of the basis set for Rb.