Numerical study of the pairing correlation of the t-J type models

We reported that the pair-pair correlation function of the two-dimensional t-J model does not have long-range d-wave superconducting correlations in t he interesting parameter range of J/t less than or equal to 0.5. The power- Lanczos method is used under the assumption of monotonic behavior. This ass umption has been well checked in the two-dimensional t-J and attractive Hub bard model. Here we re-examine this criterion of monotonic behavior of the pairing correlation function for the one-dimensional and two-leg t-J ladder where other accurate numerical results are available. The method seems to be working well.