Analytical results for the low-temperature Drude weight of the XXZ spin chain

Abstract

The spin-$1/2$ XXZ chain is an integrable lattice model and parts of its spin current can be protected by local conservation laws for anisotropies $-1<\Delta <1$. In this case, the Drude weight $D(T)$ is non-zero at finite temperatures $T$. Here we obtain analytical results for $D(T)$ at low temperatures for zero external magnetic field and anisotropies $\Delta =\cos (n\pi /m)$ with $n,m$ coprime integers, using the thermodynamic Bethe ansatz. We show that to leading orders $D(T)=D(0)-a(\Delta )T^{2K-2}-b_1(\Delta )T^2$ where $K$ is the Luttinger parameter and the prefactor $a(\Delta )$, obtained in closed form, has a fractal structure as function of anisotropy $\Delta$. The prefactor $b_1(\Delta )$, on the other hand, does not have a fractal structure and can be obtained in a standard field-theoretical approach. Including both temperature corrections, we obtain an analytic result for the low-temperature asymptotics of the Drude weight in the entire regime $-1<\Delta =\cos (n\pi /m)<1$.

16 pages, 7 figures

References in corpus (6)

• Ballistic transport in the one-dimensional Hubbard model: the hydrodynamic approach
• Conservation laws, integrability and transport in one-dimensional quantum systems
• Dynamical structure factor at small q for the XXZ spin-1/2 chain
• Exactly conserved quasilocal operators for the XXZ spin chain
• Current operators in integrable spin chains: lessons from long range deformations
• Exact real-time longitudinal correlation functions of the massive XXZ chain

Cited by in corpus (7)

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• Fine structure of the nonlinear Drude weights in the spin-1/2 XXZ chain
• Fermionic fractional quantum Hall states: A modern approach to systems with bulk-edge correspondence
• Helical Luttinger liquid on a space-time lattice
• Non-linear Transport by Bethe Bound States
• Spin Drude weight for the integrable XXZ chain with arbitrary spin