Nagaoka State and Degeneracy in the U=infinity Hubbard Model
Condensed Matter
2009-10-28 v1
Abstract
The U=infinity Hubbard model on a hypercubic lattice with exactly one hole is studied. It is seen that a degeneracy can occur in the maximal-spin sector. It is proved variationally that the Nagaoka (maximal spin) state is not a ground state, if degeneracy exists. We give an explicit construction of a variational state, an incommensurate spin-wave state, with energy lower than that of the Nagaoka state. For the case of more than one hole, a few examples are discussed where a degeneracy exists.
Keywords
Cite
@article{arxiv.cond-mat/9607126,
title = {Nagaoka State and Degeneracy in the U=infinity Hubbard Model},
author = {V. Subrahmanyam and Fajian Shi},
journal= {arXiv preprint arXiv:cond-mat/9607126},
year = {2009}
}
Comments
4 pages, Revtex, To appear in Phys. Rev. B