Dynamical mean-field theory from a quantum chemical perspective

TL;DR

This paper bridges dynamical mean-field theory (DMFT) with quantum chemistry, introducing new ab-initio Hamiltonians and impurity solvers, and applying these methods to the cubic hydrogen model to improve understanding of correlated electron systems.

Contribution

It presents a quantum chemical perspective on DMFT, including an implementation starting from an ab-initio Hartree-Fock Hamiltonian and exploring the configuration interaction hierarchy as an impurity solver.

Findings

Avoids double counting with ab-initio Hamiltonian

Uses configuration interaction as an impurity solver

Analyzes convergence issues in DMFT applications

Abstract

We investigate the dynamical mean-field theory (DMFT) from a quantum chemical perspective. Dynamical mean-field theory offers a formalism to extend quantum chemical methods for finite systems to infinite periodic problems within a local correlation approximation. In addition, quantum chemical techniques can be used to construct new ab-initio Hamiltonians and impurity solvers for DMFT. Here we explore some ways in which these things may be achieved. First, we present an informal overview of dynamical mean-field theory to connect to quantum chemical language. Next we describe an implementation of dynamical mean-field theory where we start from an ab-initio Hartree- Fock Hamiltonian that avoids double counting issues present in many applications of DMFT. We then explore the use of the configuration interaction hierarchy in DMFT as an approximate solver for the impurity problem. We also investigate some numerical issues of convergence within DMFT. Our studies are carried out in the context of the cubic hydrogen model, a simple but challenging test for correlation methods. Finally we finish with some conclusions for future directions.