Light shifts and magic wavelengths for heavy alkaline earth elements: Ba and Ra

In this paper, we investigate light shifts of heavy alkaline earth elements barium (Ba) and radium (Ra), which are interesting for optical lattice clocks and for permanent electric dipole moment searches. Detailed knowledge is required in the design of efficient loading of atoms from a magneto-optical trap into an optical dipole trap, to facilitate Doppler cooling while trapping and to achieve longer lifetimes of the trapped atoms with reduced heating rates. The wavelength dependence of light shifts of the ns ^{2 1}S ₀ ground state, the nsnp ³P ₁ and ns(n - 1)d ¹D ₂ excited states in barium (n = 6) and the n s ^{2 1}S ₀ ground state, the nsnp ³P ₁ and ns(n - 1)d ³D ₂ excited states in radium (n = 7) are calculated. Several magic wavelengths in the visible and infrared regions accessible with commercial lasers for optical dipole trapping of Ba and Ra are identified.