valid. Whether magnetic moments in ferro-pnictide materials are itinerant or localized is vigorously debated, however. In particular, the metallic temperature dependence shown by the electrical resistance in the cSDW phase of ferro-pnictide materials in addition to the absence of satellite peaks in inelastic X-ray scattering spectra is consistent with itinerant magnetism. 21 , 27 The multi-orbital Heisenberg model Hamiltonian (1) studied here is also potentially consistent with the semi-metallic nature of ferro-pnictide materials, on the other hand. Figure 1 indicates that the classical hidden ferromagnetic state remains intact in the presence of mobile holes that are prohibited from hopping between orbitals, for example. Likewise, the classical hidden N´ eel state remains intact in the presence of mobile holes that are restricted to hop between different orbitals at nearest-neighbor sites of the square lattice of iron atoms. Such limiting cases can result in low-energy electronic hole excitations near zero momentum, which are consistent with the electronic structure revealed by angle-resolved photoemission spectroscopy (ARPES) in the cSDW phase of ferro-pnictide materials. 28 Res- onant scattering of such hole excitations with the quantum-critical spin-waves studied here (Figs. 2 and 3) could also result in low-energy single-particle excitations at momenta near those associated with cSDW order. Recent ARPES studies of BaFe$_{2}$As$_{2}$ in the cSDW phase reveal the existence of low-energy electronic excitations near such momenta. 20 The mea- sured electronic spectrum there forms a Dirac cone, with a Fermi velocity of about 330 meV ˚ A. It is an order of magnitude smaller than in graphene, and it is hence consistent with strong electronic correlations. 29 It also remarkably lies inside the range of spin-wave velocities extracted from low-energy magnetic excitations near cSDW wave numbers in the doped superconducting compound BaFe$_{2}$$_{−}$$_{x}$Co$_{x}$As$_{2}$: 15 v$_{t}$ = 230 meV ˚ A and v$_{l}$ = 580 meV ˚ A (see Fig. 8). The above observations therefore indicate that injecting mobile holes into the states studied here that display hidden magnetic order (Fig. 1) potentially can account for the nature of low-energy single-particle excitations in ferro-pnictide materials. They also indicate that a description of the superconducting state of ferro-pnictide materials in terms of a doped Mott insulator 7 is possible. The author thanks Ed Rezayi, Radi Al Jishi and Elena Bascones for useful discussions. Exact diagonalizations of the J$_{0}$ - J$_{1}$ - J$_{2}$ model (1) were carried out on the SGI Altix 4700 Acknowledgments 20