  We study the unitary time evolution of antiferromagnetic order in the Hubbard
model after a quench starting from the perfect N\'eel state. In this setup,
which is well suited for experiments with cold atoms, one can distinguish
fundamentally different pathways for melting of long-range order at weak and
strong interaction. In the Mott insulating regime, melting of long-range order
occurs due to the ultra-fast transfer of energy from charge excitations to the
spin background, while local magnetic moments and their exchange coupling
persist during the process. The latter can be demonstrated by a local
spin-precession experiment. At weak interaction, local moments decay along with
the long-range order. The dynamics is governed by residual quasiparticles,
which are reflected in oscillations of the off-diagonal components of the
momentum distribution. Such oscillations provide an alternative route to study
the prethermalization phenomenon and its influence on the dynamics away from
the integrable (noninteracting) limit. The Hubbard model is solved within
nonequilibrium dynamical mean-field theory, using the density
matrix-renormalization group as an impurity solver.
