Method for measuring the6S1/2↔5D3/2magnetic-dipole-transition moment in Ba+

Abstract

We propose a method for measuring the magnetic dipole ($M1$) transition moment of the $6{S}_{1/2}(m=\ensuremath{-}1/2)\ensuremath{\leftrightarrow}5{D}_{3/2}(m=\ensuremath{-}1/2)$ transition in single trapped Ba${}^{+}$ by exploiting different symmetries in the electric quadrupole ($E2$) and $M1$ couplings between the states. The technique is adapted from a previously proposed method for measuring atomic parity nonconservation in a single trapped ion [N. Fortson, Phys. Rev. Lett. 70, 2383 (1993)]. Knowledge of $M1$ is crucial for any parity nonconservation measurement in Ba${}^{+}$, as laser coupling through $M1$ can mimic the parity-violating signal. The magnetic moment for the transition has been calculated by atomic theory and found to be dominated by electron-electron correlation effects [B. K. Sahoo et al., Phys. Rev. A 74, 062504 (2006)]. To date the value has not been verified experimentally. This proposed measurement is therefore an essential step toward a parity nonconservation experiment in the ion that will also test current many-body theory. The technique can be adapted for similar parity nonconservation experiments using other atomic ions, where the magnetic dipole moment could present similar complications.