  The orientation of the order parameter of quantum magnets can be used to
store information in a dense and efficient way. Switching this order parameter
corresponds to writing data. To understand how this can be done, we study a
precessional reorientation of the sublattice magnetization in an (an)isotropic
quantum antiferromagnet induced by an applied magnetic field. We use a
description including the leading quantum and thermal fluctuations, namely
Schwinger boson mean-field theory, because this theory allows us to describe
both ordered phases and the phases in between them, as is crucial for
switching. An activation energy has to be overcome requiring a minimum applied
field $h_\text{t}$ which is given essentially by the spin gap. It can be
reduced significantly for temperatures approaching the N\'eel temperature
facilitating switching. The time required for switching diverges when the field
approaches $h_\text{t}$ which is the signature of an inertia in the
magnetization dynamics. The temporal evolution of the magnetization and of the
energy reveals signs of dephasing. The switched state has lost a part of its
coherence because the magnetic modes do not evolve in phase.

Strongly Correlated Electrons