Dynamics of Anti-ferromagnetic Spin Order in Lattice-trapped $^{87}$Rb

Optical lattices provide a controlled environment in which to model condensed-matter systems and study strongly-correlated many-body behavior. Starting with $^{87}$Rb deep in the Mott-insulating state, we use an effective staggered field to create an antiferromagnetically-ordered (AF) many-body state in a double-well optical lattice. In $^{87}$Rb, AF order has the highest energy of any $M=0$ spin configuration in the Mott-insulator state (where $M$ is the total magnetization). Decay from this state requires low-energy excitations that are unavailable due to the Mott-insulator gap. We study the spin dynamics by varying the tunnel coupling in the lattice, to determine how well decay to other spin configurations is suppressed by the Mott-insulator gap.