Fast mode of rotated atoms in one-dimensional lattice rings

We study the rotation of atoms in one-dimensional lattice rings. In particular, the “fast mode,” where the ground-state atoms rotate faster than the stirring rotating the atoms, is studied both analytically and numerically. The conditions for the transition to the fast mode are found to be very different from those in continuum rings. We argue that these transition frequencies remain unchanged for bosonic condensates described in a mean field. We show that fermionic interactions and filling factors have a significant effect on the transition to the fast mode and the Pauli principle may suppress it altogether.