A simple method is proposed and tested for obtaining accelerated convergence of quantum systems on small lattices with N sites. The main idea is to perform exact diagonalizations with some added irrelevant parameter, and use this parameter to accelerate the convergence to the infinitelattice limit. In this paper di8'erent boundary conditions are used to improve the convergence for the Heisenber...

We present EDIpack, an exact diagonalization package to solve generic quantum impurity problems. The algorithm includes a generalization of the look-up method introduced in Ref. [1] and enables massively parallel execution matrix-vector linear operations required by Lanczos Arnoldi algorithms. show that suitable Fock basis organization is crucial optimize inter-processors communication distribu...

Exact diagonalization study of the two-dimensional t − J−Holstein model (Received today) We study by exact diagonalization the two-dimensional t − J−Holstein model near quarter filling by retaining only few phonon modes in momentum space. This truncation allows us to incorporate the full dynamics of the retained phonon modes. The behavior of the kinetic energy, the charge structure factor and o...