2008/04/15 by J. M. P. Carmelo, Carmelo, J. M. P., M. J. Sampaio +1
Chemistry · Mathematics · Physics and Astronomy · #Algebraic structures and combinatorial models #FOS: Physical sciences #Molecular spectroscopy and chirality #Nonlinear Waves and Solitons #Strongly Correlated Electrons (cond-mat.str-el)
paper · pdf · doi:10.48550/arxiv.0804.2358
openalex publication_date 2008/04/15 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In this paper a description of the Hubbard model on the square lattice with nearest-neighbor transfer integral t, on-site repulsion U, and Na2≫ 1 sites consistent with its exact global SO(3)× SO(3)× U(1) symmetry is constructed. Our studies profit from the interplay of that recently found global symmetry of the model on any bipartite lattice with the transformation laws under a suitable electron - rotated-electron unitary transformation of a well-defined set of operators and quantum objects. For U/4t>0 the occupancy configurations of these objects generate the energy eigenstates that span the one- and two-electron subspace. Such a subspace as defined in this paper contains nearly the whole spectral weight of the excitations generated by application onto the zero-spin-density ground state of one- and two-electron operators. Our description involves three basic objects: charge c fermions, spin-1/2 spinons, and η-spin-1/2 η-spinons. Alike in chromodynamics the quarks have color but all quark-composite physical particles are color-neutral, the η-spinon (and spinons) that are not invariant under that transformation have η spin 1/2 (and spin 1/2) but are part of η-spin-neutral (and spin-neutral) 2ν-η-spinon (and 2ν-spinon) composite ην fermions (and sν fermions) where ν=1,2,... is the number of η-spinon (and spinon) pairs.The description introduced here is consistent with a Mott-Hubbard insulating ground state with antiferromagnetic long-range order for half filling at x=0 hole concentration and a ground state with short-range spin order for a well-defined range of finite hole concentrations x>0.