Thermal transport in the anisotropic Heisenberg chain with S = 12 and nearest-neighbor inte.pdfVIP

1 Thermal transport in the anisotropic Heisenberg chain with S = 1/2 and nearest-neighbor interactions D. L. Huber Department of Physics, University of Wisconsin-Madison, Madison, WI 53706 Abstract The purpose of this note is to connect early work on thermal transport in spin-1/2 Heisenberg chains with uniaxial exchange anisotropy and nearest-neighbor interactions that was based on a moment analysis of the Fourier transform of the energy density correlation function with subsequent studies that make use of thermal current correlation functions. PACS: 66.70.-f, 75.10.-b, 75.10.Jm, 75.40.Gb Key words: thermal transport; spin-1/2, anisotropic Heisenberg chain; energy density; thermal current; correlation functions Corresponding author: D. L. Huber, Physics Department, University of Wisconsin-Madison, 1150 University Avenue, Madison, WI 53706, USA E-mail huber@src.wisc.edu; phone: 608-265-4035; fax 608-265-2334 2 I. Introduction Recent experimental [1] and theoretical studies [2,3] have focused renewed attention on the unusual thermal transport properties of anisotropic spin-1/2 Heisenberg chains with nearest-neighbor interactions. The first theoretical investigations of the transport involved an analysis of the second and fourth moments of the energy density correlation function [4,5]. In Ref. 4, it was found that the thermal transport was non- diffusive in the infinite temperature limit for all values of the anisotropy (excluding the Ising limit). The calculations in Ref. 5 extended the results of Ref. 4 for the isotropic chain to finite temperatures. Subsequently, Th. Niemeijer and H. A. W. van Vianen [6] showed that the thermal current operator for the anisotropic, spin-1/2 Heisenberg chain with nearest-neighbor interactions was a constant of the motion in the absence of a field. They also found that in the presence of a field, the thermal current operator was the sum