In a potential of this type, transitions between states can be suppressed by tuning the potential to the “magic wavelength.” In a potential of this type, the ratio between an interaction matrix element, U, and a tunneling parameter, J, has a critical value denoting a phase transition. Rubidium atoms in a potential of this type transition between (-5[1])superfluid and Mott insulator states as the potential depth is increased. An alternative to (-5[1])the fountain (15[1])method (15[1])for making atomic clocks involves a potential of this type which traps atoms using the (*) AC Stark effect. The interference of crossed (10[1])laser beams forms an (-5[1])“optical” analogue of these structures, (10[1])which in 3 dimensions come (10[1])in 14 types and are built from primitive, face-centered, or body-centered unit cells. For 10 (-5[2])points, give (10[1])this (-5[1])term for the periodic structure formed by (10[1])crystals. ■END■ (10[1])