Exact diagonalization library for quantum electron models

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

Parallel in time dynamics with quantum annealers

Recent years have witnessed an unprecedented increase in experiments and hybrid simulations involving quantum computers. In particular, quantum annealers. There exist a plethora of algorithms promising to outperform classical computers in the near-term future. Here, we propose a parallel in time approach to simulate dynamical systems designed to be executed already on present-day quantum annealers. In essence, purely classical methods for solving dynamics systems are serial. Therefore, their parallelization is substantially limited. In the presented approach, however, the time evolution is rephrased as a ground-state search of a classical Ising model. Such a problem is solved intrinsically in parallel by quantum computers. The main idea is exemplified by simulating the Rabi oscillations generated by a two-level quantum system (i.e. qubit) experimentally

Exact diagonalization library for quantum electron models

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