Determination of magic wavelengths for the $7s ~ {^2}S_{1/2}-7p ~ {^2}P_{3/2,1/2}$ transitions in Fr atom

Abstract

Magic wavelengthsfor the $7S_{1/2}-7P_{1/2,3/2}$ transitions in Fr were reported by Dammalapati \textit{et al.} in [Phys. Rev. A 93, 043407 (2016)]. These $\lambda_{\rm{magic}}$ were determined by plotting dynamic polarizabilities ($\alpha$) of the involved states with the above transitions against a desired range of wavelength. Electric dipole (E1) matrix elements listed in [J. Phys. Chem. Ref. Data 36, 497 (2007)], from the measured lifetimes of the $7P_{1/2,3/2}$ states and from the calculations considering core-polarization effects in the relativistic Hartree-Fock (HFR) method, were used to determine $\alpha$. However, contributions from core correlation effects and from the E1 matrix elements of the $7P-7S$, $7P-8S$ and $7P-6D$ transitions to $\alpha$ of the $7P$ states were ignored. In this work, we demonstrate importance of these contributions and improve accuracies of $\alpha$ further by replacing the E1 matrix elements taken from the HFR method by the values obtained employing relativistic coupled-cluster theory. Our static $\alpha$ are found to be in excellent agreement with the other available theoretical results; whereas substituting the E1 matrix elements used by Dammalapati \textit{et al.} give very small $\alpha$ values for the $7P$ states. Owing to this, we find disagreement in $\lambda_{\rm{magic}}$ reported by Dammalapati \textit{et al.} for linearly polarized light; especially at wavelengths close to the D-lines and in the infrared region. As a consequence, a $\lambda_{\rm{magic}}$ reported at 797.75 nm which was seen supporting a blue detuned trap in their work is now estimated at 771.03 nm and is supporting a red detuned trap. Also, none of our results match with the earlier results for circularly polarized light. Moreover, our static values of $\alpha$ will be very useful for guiding experiments to carry out their measurements.