Spin conductivity in almost integrable spin chains

Abstract

The spin conductivity in the integrable spin-1/2 XXZ-chain is known to be infinite at finite temperatures T for anisotropies -1 < Delta < 1. Perturbations which break integrability, e.g. a next-nearest neighbor coupling J', render the conductivity finite. We construct numerically a non-local conserved operator J_parallel which is responsible for the finite spin Drude weight of the integrable model and calculate its decay rate for small J'. This allows us to obtain a lower bound for the spin conductivity sigma_s >= c(T) / J'^2, where c(T) is finite for J' to 0. We discuss the implication of our result for the general question how non-local conservation laws affect transport properties.

6 pages, 5 figures

References in corpus (5)

• Magnetothermal transport in the spin-1/2 chains of copper pyrazine dinitrate
• Fragility of String Orders
• Lower bounds for the conductivities of correlated quantum systems
• Thermal conductivity of one-dimensional spin-1/2 systems
• Anisotropic field dependence of the magnetic transition in Cu2Te2O5Br2

Cited by in corpus (3)

• A real-time study of diffusive and ballistic transport in spin-1/2 chains using the adaptive time-dependent density matrix renormalization group method
• AC magnetization transport and power absorption in non-itinerant spin chains
• Large thermomagnetic effects in weakly disordered Heisenberg chains