Magic wavelengths for the $ns-np$ transitions in alkali-metal atoms

Extensive calculations of the electric-dipole matrix elements in alkali-metal atoms are conducted using the relativistic all-order method. This approach is a linearized version of the coupled-cluster method, which sums infinite sets of many-body perturbation theory terms; it is one of the most accurate methods currently being used in atomic structure calculations. All allowed transitions between four lowest $s, p_{1/2}, p_{3/2}$ states and three lowest $d_{3/2}, d_{5/2}$ states are considered and an estimate of the accuracy of the calculation is conducted. The results are used for the high-precision calculation of the frequency-dependent polarizabilities of the alkali-atoms in excited states. We find ``magic'' wavelengths in alkali-metal atoms for which the $ns$ and $np_{1/2,3/2}$ atomic levels have the same ac-Stark shifts, which facilitates state-insensitive optical cooling and trapping.