Density-Matrix Renormalization-Group Analysis of Kondo and XY models

Naokazu Shibata, Tetsuya Mutou, Kazuo Ueda

Changtao Hou, Vivek Aji, Chandra Mohan Varma

S. Moukouri, Laurent G. Caron, C. Bourbonnais +1 more

A recently proposed density-matrix renormalization group is used to investigate the ground-state properties of the Kondo-necklace Hamiltonian. It represents a chain of XY interacting pseudospins that are Kondo coupled (J) to localized spins. The spin gap as well as the short- and long-range spin correlation functions are consistent with the existence of a smooth crossover at J\ensuremath{\approxeq}0.5. For J\ensuremath{\le}0.5, the gap depends exponentially on ${\mathit{J}}^{\mathrm{\ensuremath{-}}1/2}$ and the in-plane correlation function of the localized spins shows RKKY oscillations while the z one falls monotonically in contrast to the XY behavior. The correlation length diverges at J=0. For J\ensuremath{\ge}0.5, the gap is linearly increasing with J, and the system is made of nearly independent singlets.

Paul Harten, P. Surànyi

R. M. Noack, Steven R. White, Douglas J. Scalapino

Ibha Chatterjee

A previously unsolved problem has been solved numerically using transfer matrix renormalization group analysis, based on a density matrix renormalization group idea. This calculation leads to a high-precision prediction of the value of susceptibility in the x - or y - directions of an XY spin-chain, because in the calculation the transfer matrix idea is incorporated and a thermodynamic limit is ensured. From this calculation the susceptibility at zero temperature is predicted for a spin-½ antiferromagnetic XY model in one dimension.