Low Temperature Lanczos Method

TL;DR

This paper introduces a modified finite temperature Lanczos method for accurately computing dynamical and static properties of strongly correlated electron systems across all temperatures, enhancing previous techniques.

Contribution

The paper presents a new low temperature Lanczos method that improves finite temperature calculations for strongly correlated systems, complementing existing approaches.

Findings

Accurate calculation of static spin correlations and optical conductivity in the 1D Hubbard model.

Demonstration of the connection between ground state and finite temperature methods.

Extension of spectral functions to infinite systems using Cluster Perturbation Theory.

Abstract

We present a modified finite temperature Lanczos method for the evaluation of dynamical and static quantities of strongly correlated electron systems that complements the finite temperature method (FTLM) introduced by Jaklic and Prelovsek for low temperatures. Together they allow accurate calculations at any temperature with moderate effort. As an example we calculate the static spin correlation function and the regular part of the optical conductivity of the one dimensional Hubbard model at half-filling and show in detail the connection between the ground state and finite temperature method. By using Cluster Perturbation Theory (CPT), the finite temperature spectral function is extended to the infinite system, clearly exhibiting the effects of spin-charge separation.