Exact diagonalization library for quantum electron models

Abstract

We present an exact diagonalization C++ template library (EDLib) for solving quantum electron models, including the single-band finite Hubbard cluster and the multi-orbital impurity Anderson model. The observables that can be computed using EDLib are single particle Green's functions and spin–spin correlation functions. This code provides three different types of Hamiltonian matrix storage that can be chosen based on the model. Program summary: Program Title: EDLib Program Files doi: http://dx.doi.org/10.17632/633698b4g2.1 Licensing provisions: MIT Programming language: C++, MPI External routines: ARPACK-NG, ALPSCore library (Gaenko et al., 2016) Nature of problem: The finite Hubbard and Anderson models play an essential role in the description of strongly correlated many-particle systems. These models consist of a small number of localized orbitals with Coulomb interaction between electrons and (in case of the Anderson model) non-interacting bath energy levels. The finite Hubbard cluster can be used to study molecular magnets, such as Mn12, Fe4, Mn4, and V15, which are currently of interest due to their potential for use in novel technologies such as molecular electronics, solar energy harvesting, thermoelectrics, sensing, and other applications (Sakon et al., 2004; Accorsi et al., 2006; Friedman et al., 1996) [1–3]. The Anderson model can be used to study impurities adsorbed on surfaces (Iskakov et al., 2015) [4] and appears as an impurity model in the Dynamic Mean Field Theory (Georges et al., 1996) [5]. Solution method: The OpenMP and MPI parallelized versions of the finite temperature Lanczos diagonalization method are used to diagonalize Hamiltonian matrix and to compute observables. © 2017 Elsevier B.V.