Spin-charge coupling in quantum wires at zero magnetic field

TL;DR

This paper investigates the dynamic charge response in nonlinear spin-1/2 Luttinger liquids at zero magnetic field, revealing effects of nonlinearity and temperature on charge and spin excitations and their impact on Coulomb drag.

Contribution

It introduces an approximation for the charge response that includes nonlinearity effects and analyzes the temperature-dependent broadening of spin and charge peaks.

Findings

Broadening of the charge peak due to two-holon excitations.

Asymmetric line shape of the two-spinon peak at zero temperature.

Temperature-induced broadening of the spin peak by diffusion.

Abstract

We discuss an approximation for the dynamic charge response of nonlinear spin-1/2 Luttinger liquids in the limit of small momentum. Besides accounting for the broadening of the charge peak due to two-holon excitations, the nonlinearity of the dispersion gives rise to a two-spinon peak, which at zero temperature has an asymmetric line shape. At finite temperature the spin peak is broadened by diffusion. As an application, we discuss the density and temperature dependence of the Coulomb drag resistivity due to long-wavelength scattering between quantum wires.