Magic and tune-out wavelengths for atomic francium

Abstract

The frequency dependent polarizabilities of the francium atom are calculated from the available data of energy levels and transition rates. Magic wavelengths for the state insensitive optical dipole trapping are identified from the calculated light shifts of the $7s~^2S_{1/2}$, $7p~^2P_{1/2, 3/2}$ and $8s~^{2}S_{1/2}$ levels of the $7s~^{2}S_{1/2}-7p~^{2}P_{1/2,3/2}$ and $7s~^{2}S_{1/2}-8s~^{2}S_{1/2}$ transitions, respectively. Wavelengths in the ultraviolet, visible and near infrared region is identified that are suitable for cooling and trapping. Magic wavelengths between 600-700~nm and 700-1000~nm region, which are blue and red detuned with the $7s-7p$ and $7s-8s$ transitions are feasible to implement as lasers with sufficient power are available. In addition, we calculated the tune-out wavelengths where the ac polarizability of the ground $7s~^{2}S_{1/2}$ state in francium is zero. These results are beneficial as laser cooled and trapped francium has been in use for fundamental symmetry investigations like searches for an electron permanent electric dipole moment in an atom and for atomic parity non-conservation.Comment: 9 pages, 5 figures, accepted for publication in Physical Review

Determination of magic wavelengths for the7s S1/22−7p PSingh1, Sahoo2, Arora3 2016Phys. Rev. A13090View full textAdd to dashboardCite

“…Correspondingly, we expect that the dynamic polarizabilities evaluated in our calculations are also accurate enough to determine λ magic for the 7S 1/2 − 7P 1/2,3/2 transitions in Fr. Now to fathom about the accuracies in the estimated α n 's of the considered states in Fr by Dammalapati et al [13], we consider the E1 matrix elements referred in their paper and use the experimental energies to reproduce the corresponding static polarizability values. As discussed in Sec.…”

“…II(A) and II(B) of Ref. [13], they take into account the E1 matrix elements of the 7S − nP transitions with n = 7 − 20 from Ref. [23] to evaluate dynamic α n of the ground state.…”

“…In our previous works, we have also theoretically determined λ magic of Dlines of the lighter alkali atoms for both linearly and circularly polarized light [18][19][20][21][22]. With the same objective, Dammalapati et al [13] have recently identified λ magic for the 7S 1/2 − 7P 1/2,3/2 and 7S 1/2 − 8S 1/2 transitions in Fr considering both linearly and circularly polarized light. On this rationale, they have used transition rates compiled by Sansonetti in Ref.…”

“…Similar to other alkali atoms D-lines in Fr atom are used for laser cooling and trapping experiments, which leads to the easy accessibility of this atom for its application in probing new physics of fundamental particles [13][14][15]. Therefore, it is certainly attainable to develop cooling and trapping techniques for the Fr atoms in near future.…”

“…In addition to this, we use more accurate values of the electric dipole (E1) matrix elements for the higher excited states from a relativistic coupled-cluster (RCC) theory as compared to the values used from a lower order many-body method in [13]. In order to validate our results, we have also estimated static dipole polarizability values of the ground and 7P 1/2,3/2 states and compare them against the other available high precision calculations.…”