Possibility of triple magic trapping of clock and Rydberg states of divalent atoms in optical lattices

We predict the possibility of ‘triply magic’ optical lattice trapping of neutral divalent atoms. In such a lattice, the ##IMG## [http://ej.iop.org/images/0953-4075/49/14/144004/jpbaa2c58ieqn1.gif] {${}^{1}{{\rm{S}}}_{0}$} and ##IMG## [http://ej.iop.org/images/0953-4075/49/14/144004/jpbaa2c58ieqn2.gif] {${}^{3}{{\rm{P}}}_{0}$} clock states and an additional Rydberg state experience identical optical potentials, fully mitigating detrimental effects of the motional decoherence. In particular, we show that this triply magic trapping condition can be satisfied for Yb atom at optical wavelengths and for various other divalent systems (Ca, Mg, Hg and Sr) in the UV region. We assess the quality of triple magic trapping conditions by estimating the probability of excitation out of the motional ground state as a result of the excitations between the clock and the Rydberg states. We also calculate trapping laser-induced photoionization rates of divalent Rydberg atoms at magic frequencies. We find that such rates are below the radiative spontaneous-emission rates, due to the presence of Cooper minima in photoionization cross-sections.