2010/03/24 by J. P. Carmelo, Carmelo, J. P.
Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #FOS: Physical sciences #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #Strongly Correlated Electrons (cond-mat.str-el)
paper · pdf · doi:10.48550/arxiv.1003.4619
openalex publication_date 2010/03/24 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In this paper we consider the simplified form that a recently introduced general operator description of the Hubbard model on the square lattice with Na2≫ 1 sites, effective transfer integral t, and onsite repulsion U has in a suitable one- and two-electron subspace. Such an operator description is that consistent with the model exact global symmetry recently extended to SO(3)× SO(3)× U(1). There is a large consensus that in the thermodynamic limit Na2→∞ long-range antiferromagnetic order occurs in the spin-density m=0 ground state of the half-filled Hubbard model on the square lattice. Here we find that the corresponding spontaneous symmetry breaking lowers the symmetry of such a state from SO(3)× SO(3)× U(1) for Na2≫ 1 large but finite to [U(2)× U(1)]/Z22 ≡ [SO(3)× U(1)× U(1)]/Z2 for Na2→∞. Moreover, we argue that the spin effective lattice being identical to the original lattice is a necessary condition for the occurrence of ground-state long-range antiferromagnetic order in the limit Na2→∞. Consistently, strong evidence is provided that for very small hole concentration 0