PairDiag: An exact diagonalization program for solving general pairing Hamiltonians

We present a program for solving exactly the general pairing Hamiltonian based on diagonalization. The generates seniority-zero shell-model-like basis vectors via ‘01’ inversion algorithm. matrix is constructed in this space. evaluates all non-zero elements of “on fly” using scattering operator and search diagonalized by iterative Lanczos OpenMP parallel thus developed, PairDiag, can efficiently calculate ground-state eigenvalue eigenvector both even-mass odd-mass system. packaged Fortran module, which makes it easy to use replace BCS approximation standard self-consistent mean field calculations. For systems with dimension around 108, calculation be done within hours desktop computers. Program Title: PairDiag. Files doi: https://doi.org/10.17632/dzzspfszsh.1 Licensing provisions: CC NC 3.0. Programming language: 95. Nature problem: numerically exact solution solved diagonalization configuration spaces fixed seniority. Solution method: constructs space algorithm, diagonalizes plus QR Restrictions: total number orbits involved must less than 63, that calculated restricted local RAM condition.