Dynamics in One-Dimensional Spin Systems - Density-Matrix Renormalization Group Study

TL;DR

This paper uses the dynamical density-matrix renormalization group method to study the dynamical properties of the one-dimensional S=1/2 Heisenberg model with magnetic fields, providing near-exact results for large chains.

Contribution

It demonstrates the application of DDMRG to compute dynamical spin structure factors in large 1D spin chains with different boundary conditions.

Findings

Accurate dynamical spin structure factors for large chains

Comparison of open-end and periodic boundary conditions

Near-exact results in the thermodynamic limit

Abstract

We study the one-dimensional $S=1/2$ Heisenberg model with a uniform and a staggered magnetic fields, using the dynamical density-matrix renormalization group (DDMRG) technique. The DDMRG enables us to investigate the dynamical properties of chain with lengths up to a few hundreds, and the results are numerically exact in the same sense as 'exact diagonalization' results are. Thus, we can analyze the low-energy spectrum almost in the thermodynamic limit. In this work, we calculate the dynamical spin structure factor and demonstrate the performance of the DDMRG method applying the open-end boundary condition as well as the periodic boundary condition.