Chebyshev Matrix Product State Impurity Solver for the Dynamical Mean-Field Theory

TL;DR

This paper introduces a Chebyshev matrix product state impurity solver for dynamical mean-field theory, achieving precise spectral functions with improved efficiency and technical insights into the method's relation to real-time evolution.

Contribution

The paper presents a novel Chebyshev MPS impurity solver for DMFT, enhancing accuracy and computational efficiency over existing methods.

Findings

Quantitatively precise spectral functions obtained

Technical improvements in truncation and rescaling schemes

Relation of Chebyshev iteration to real-time evolution established

Abstract

We compute the spectral functions for the two-site dynamical cluster theory and for the two-orbital dynamical mean-field theory in the density-matrix renormalization group (DMRG) framework using Chebyshev expansions represented with matrix product states (MPS). We obtain quantitatively precise results at modest computational effort through technical improvements regarding the truncation scheme and the Chebyshev rescaling procedure. We furthermore establish the relation of the Chebyshev iteration to real-time evolution, and discuss technical aspects as computation time and implementation in detail.