New implementation of hybridization expansion quantum impurity solver based on Newton-Leja interpolation polynomial

TL;DR

This paper presents a novel hybridization expansion quantum impurity solver using Newton-Leja interpolation, significantly improving efficiency and memory usage for multi-band models in dynamical mean-field theory.

Contribution

The new implementation employs Newton interpolation at Leja points, reducing computational complexity and memory requirements compared to existing methods.

Findings

Outperforms previous algorithms for five or more bands

Efficiently computes local Hamiltonian time evolution

Successfully applied to electronic structure of SrVO3

Abstract

We introduce a new implementation of hybridization expansion continuous time quantum impurity solver which is relevant to dynamical mean-field theory. It employs Newton interpolation at a sequence of real Leja points to compute the time evolution of the local Hamiltonian efficiently. Since the new algorithm avoids not only computationally expansive matrix-matrix multiplications in conventional implementations but also huge memory consumptions required by Lanczos/Arnoldi iterations in recently developed Krylov subspace approach, it becomes advantageous over the previous algorithms for quantum impurity models with five or more bands. In order to illustrate the great superiority and usefulness of our algorithm, we present realistic dynamical mean-field results for the electronic structures of representative correlated metal SrVO$_{3}$.