The Drude weight of the spin-1/2 XXZ chain: density matrix renormalization group versus exact diagonalization
Abstract
We revisit the problem of the spin Drude weight D of the integrable spin-1/2 XXZ chain using two complementrary approaches, exact diagonalization (ED) and the time-dependent density-matrix renormalization group (tDMRG). We pursue two main goals. First, we present extensive results for the temperature dependence of D. By exploiting time translation invariance within tDMRG, one can extract D for significantly lower temperatures than in previous tDMRG studies. Second, we discuss the numerical quality of the tDMRG data and elaborate on details of the finite-size scaling of the ED results, comparing calculations carried out in the canonical and grand-canonical ensembles. Furthermore, we analyze the behavior of the Drude weight as the point with SU(2)-symmetric exchange is approached and discuss the relative contribution of the Drude weight to the sum rule as a function of temperature.
Keywords
Cite
@article{arxiv.1301.6401,
title = {The Drude weight of the spin-1/2 XXZ chain: density matrix renormalization group versus exact diagonalization},
author = {C. Karrasch and J. Hauschild and S. Langer and F. Heidrich-Meisner},
journal= {arXiv preprint arXiv:1301.6401},
year = {2015}
}
Comments
Revised version, additional ED and DMRG data for negative Delta, DMRG data for lower temperatures, discussion of Benz et al. 2005 corrected