Regensburg 2019 – wissenschaftliches Programm
TT 30.7: Vortrag
Dienstag, 2. April 2019, 15:30–15:45, H4
The spin Drude weight of the XXZ chain and generalized hydrodynamics — •Yahya Öz1, Andrew Urichuk2, Andreas Klümper1, and Jesko Sirker2 — 1Bergische Universität Wuppertal, Deutschland — 2University of Manitoba, Canada
Based on a generalized free energy we derive exact thermodynamic Bethe ansatz formulas for the expectation value of the spin current, the spin current-charge, charge-charge correlators, and consequently the Drude weight. These formulas agree with recent conjectures within the generalized hydrodynamics formalism. They follow, however, directly from a proper treatment of the operator expression of the spin current. The result for the Drude weight is identical to the one obtained 20 years ago based on the Kohn formula and TBA. We numerically evaluate the Drude weight for anisotropies Δ=cosγ with γ=π n/m, n≤ m integer and coprime. We prove, furthermore, that the high-temperature asymptotics for general γ=π n/m obtained by analysis of the quantum transfer matrix eigenvalues agrees with the bound which has been obtained by the construction of quasi-local charges.