We show that the physical subspace in the Z2-slave-spin theory is conserved
under the time evolution of the system. Thus, when restricted to the physical
subspace, this representation gives a complete and consistent description of
the original problem. In addition, we review two known examples from the
existing literature in which the projection onto the physical subspace can be
relaxed: (i) the non-interacting limit in any dimension at half filling and
(ii) the interacting model in the infinite dimensional limit at half filling.
In both cases, physical observables are correctly obtained without explicit
treatment of the constraints which define the physical subspace. In these
examples, correct results are obtained, despite the fact that unphysical states
enter the solution.Comment: Reply to http://link.aps.org/doi/10.1103/PhysRevB.87.03710