History of HΦ
An exact diagonalization approach is one of the most reliable numerical tools to solve quantum lattice hamiltonians without any approximation. For last few decades, a numerical diagonalization package for quantum spin hamiltonians, TITPACK developed by Prof. Hidetoshi Nishimori in Tokyo Institute of Technology, has been widely used in the condensed-matter physics community. HΦ, a flexible diagonalization package for solving quantum lattice hamiltonians, has been developed to be such a descendant of the pioneering package TITPACK.
Features of HΦ
The Lanczos method for calculations of the ground state and few excited states properties, and finite temperature calculations based on thermal pure quantum states are implemented in HΦ, with an easy-to-use and flexible user interface. By using HΦ, you can analyze a wide range of quantum lattice hamiltonians including simple Hubbard and Heisenberg models, multi-band extensions of the Hubbard model, exchange couplings that break SU(2) symmetry of quantum spins such as Dzyaloshinskii-Moriya and Kitaev interactions, and Kondo lattice models describing itinerant electrons coupled with quantum spins.
Future of HΦ
Although present release of HΦ (HΦ ver.0.1) is parallelized with OpenMP for shared-memory architectures, hybrid parallel versions with MPI and OpenMP will be released within the fiscal year. In the near future, subroutines for calculating excitation spectra will be implemented in HΦ. HΦ will also provide a numerical solver for impurity problems in the dynamical mean-field theory, a cluster solver for the cluster perturbation theory, and so on.
Dream of developers
Our goal is to develop HΦ as a standard diagonalization program package in condensed-matter physics community including experimental researchers.