%0 Journal Article %T Exact Results on Itinerant Ferromagnetism in Multi-orbital Systems on Square and Cubic Lattices %A Yi Li %A Elliott H. Lieb %A Congjun Wu %J Physics %D 2013 %I arXiv %R 10.1103/PhysRevLett.112.217201 %X We study itinerant ferromagnetism in multi-orbital Hubbard models in certain two-dimensional square and three-dimensional cubic lattices. In the strong coupling limit where doubly occupied orbitals are not allowed, we prove that the fully spin-polarized states are the unique ground states, apart from the trivial spin degeneracies, for a large region of fillings factors. Possible applications to p-orbital bands with ultra-cold fermions in optical lattices, and electronic 3d-orbital bands in transition-metal oxides, are discussed. %U http://arxiv.org/abs/1310.4391v3