C. Karrasch, J. Hauschild, S. Langer, F. Heidrich-Meisner
We revisit the problem of the spin Drude weight D of the integrable spin-1/2 XXZ Heisenberg chain using two complementrary approaches, exact diagonalization (ED) and the time-dependent density-matrix renormalization group (tDMRG). The aim of our paper is three-fold: First, we present extensive results for the temperature-dependence of D. 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. Third, we analyze the behavior of the Drude weight as the point with SU(2)-symmetric exchange is approached.
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http://arxiv.org/abs/1301.6401
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