A Fermi-degenerate three-dimensional optical lattice clock

Making a denser optical lattice clock Some of today's most advanced clocks are made up of large numbers of atoms lined up in a one-dimensional (1D) optical lattice. The numbers improve clock stability, but atomic interactions can limit accuracy. Campbell et al. loaded their fermionic strontium atoms into a 3D optical lattice. The low temperatures and strong interactions ensured that the atoms avoided one another, resulting in a neat pattern where each lattice site was occupied by exactly one atom. This ordering reduced the influence of interactions on the clock's accuracy, whereas the high density of atoms enabled by the 3D geometry improved the precision. Science , this issue p. 90