Correlations in a Two-Chain Hubbard Model
Correlations in a Two-Chain Hubbard Model
Equal-time spin-spin and pair-field correlation functions are calculated for a two-chain Hubbard model using a density-matrix numerical renormalization group approach. At half filling, the antiferromagnetic and pair-field correlations both decay exponentially with the pair field having a much shorter correlation length. This is consistent with a gapped spin-liquid ground state. …