Magic wavelengths for laser trapping of boson isotopes of alkaline-earth Sr,
Ca and Mg atoms are investigated while considering terahertz clock transitions
between the 3P0,3P1,3P2 metastable triplet states. Our
calculation shows that magic wavelengths of trapping laser do exist. This
result is important because those metastable states have already been used to
realize accurate clocks in the terahertz frequency domain. Detailed discussions
for magic wavelength for terahertz clock transitions are given in this paper.Comment: 7 page