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arXiv · 1301.6401

The Drude weight of the spin-1/2 XXZ chain: density matrix renormalization group versus exact diagonalization

C. Karrasch·J. Hauschild·S. Langer·F. Heidrich-Meisner
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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.

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C. Karrasch, J. Hauschild, S. Langer, F. Heidrich-Meisner. 2013-01-27. The Drude weight of the spin-1/2 XXZ chain: density matrix renormalization group versus exact diagonalization. https://doi.org/10.1103/physrevb.87.245128

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