Many intriguing behaviors, such as high-temperature superconductivity, result from the strong interactions among particles in a many-body system. Theorists have explored those complex interactions with model Hamiltonians, but real-world defects make physical systems imperfect realizations of the models. And time and memory constraints limit computer simulations of quantum behavior to just a handful of atoms.
A tantalizing alternative is to use small clouds of atoms, typically tens of thousands, cooled to nanokelvin temperatures, to study the complex physics of strongly correlated systems. To simulate the structure of solids, researchers can trap atomic gases in a periodic array of optical potentials created by intersecting laser beams, much as eggs are confined by the corrugations of an egg carton. The optical arrays can be nearly defect free, and particle interactions can be tuned to explore the system behavior. Depending on whether the atom is a fermion or a boson, it might represent...
