Quantum impurity models with the Coupled Cluster Method

TL;DR

This paper explores the application of the Coupled Cluster Method to quantum impurity models, demonstrating its effectiveness in accurately capturing ground-state properties and comparing favorably with exact and perturbative methods.

Contribution

It introduces the use of Coupled Cluster techniques for quantum impurity models and evaluates their performance against established methods.

Findings

Coupled Cluster Method accurately models ground states of impurity systems.

CCM results agree well with exact Green's function calculations.

CCM shows promise as a tool for quantum impurity problems.

Abstract

We investigate the ground-state properties of the Anderson single impurity model (finite Coulomb impurity repulsion) with the Coupled Cluster Method. We consider different CCM reference states and approximation schemes and make comparison with exact Green's function results for the non-interacting model and with Brillouin-Wigner perturbation theory for the full interacting model. Our results show that coupled cluster techniques are well suited to quantum impurity problems.