A free software library for numerical diagonalization of quantum spin systems. Although the programs are based on TITPACK, they have been completely rewritten in C/C++ and several extensions have been added. It can handle, for example, the Heisenberg model, the Hubbard model, and the t-J model. This library supports dimension reduction of matrices exploiting symmetries, and it can run in parallel computing environments.
A open-source application of first-principles calculation for the electronic structure, using the KKR method, a variant of Green’s function method. It is based on the density functional theory and is applicable to crystals and surfaces. The coherent potential approximation (CPA) is adopted, so it can handle not only periodic systems, but also disordered alloys. It can also handle spin-orbit interaction and non-collinear magnetism.
STATE is a first-principles plane-wave pseudo-potential code. It provides electronic state calculations and molecular dynamics simulations. This code is suitable for simulating chemical reactions at solid surfaces and solid–liquid interfaces, i.e., It is able to investigate reaction paths and activation barriers of chemical processes at interfaces. It can also include Van der Waals corrections to conventional density functional theory.
Open source software for massively parallel quantum chemistry calculations. Energies and geometries of nano-sized molecules can be calculated without fragmentation. The program supports Hartree-Fock, density functional theory, and second-order Møller-Plesset perturbation theory calculations. The input format, execution method, and program structure are simple, and frequently used routines can be easily extracted.
An open-source application for simulation of low-dimensional interacting electron models based on density-matrix renormalization group (DMRG). For effective models of one-dimensional quantum systems and impurity systems, this application can treat not only physical quantities of ground states but also time evolution and finite-temperature physical quantities. The program is coded in C++, and can be called from MATLAB scripts.
A sparse-modeling tool for computing the spectral function from the imaginary-time Green function. It removes statistical errors in quantum Monte Carlo data, and performs a stable analytical continuation. The obtained spectral function fulfills the non-negativity and the sum rule. The computation is fast and free from tuning parameters.