ec 1 99 6 Monte Carlo study of the pairing interaction in the two - leg Hubbard ladder

Monte Carlo calculations of the irreducible particle-particle interaction on a two-leg Hubbard ladder doped near half-filling are reported. As the temperature is lowered, this interaction develops structure in momentum space similar to the magnetic susceptibility χ(q) and reflects the development of strong short-range antiferromagnetic correlations. Using this interaction, the eigenfunction of the leading singlet pair eigenvalue is found to have d x 2 −y 2 like symmetry. The single-particle spectral weight is also shown to peak near (π, 0) and (0, π) when the ratio of the inter-to intra-chain hopping t ⊥ /t ≃ 1.5, leading to an increased tendency for pairing.