Coordinate-space solution of the Skyrme–Hartree–Fock– Bogolyubov equations within spherical symmetry. The program HFBRAD (v1.00)

Abstract

We describe the first version (v1.00) of the code hfbrad which solves the Skyrme–Hartree–Fock or Skyrme–Hartree–Fock–Bogolyubov equations in the coordinate representation with spherical symmetry. A realistic representation of the quasiparticle wave functions on the space lattice allows calculations to be performed up to the particle drip lines. Zero-range density-dependent interactions are used in the pairing channel. The pairing energy is calculated by either using a cut-off energy in the quasiparticle spectrum or the regularization scheme proposed by A. Bulgac and Y. Yu. Program summary Title of the program: hfbrad (v1.00) Catalogue indentifier:ADVM Program summary URL: http://cpc.cs.qub.ac.uk/summaries/ADVM Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Licensing provisions: none Computers on which the program has been tested: Pentium-III, Pentium-IV Operating systems: LINUX, Windows Programming language used:FORTRAN-95 Memory required to execute with typical data: 30 MBytes No. of bits in a word: The code is written with a type real and uses the intrinsic function selected_real_kind at the beginning of the code to ask for at least 12 significant digits. This can be easily modified by asking for more significant digits if the architecture of the computer can handle it. No. of processors used:1 Has the code been vectorized?:No No. of bytes in distributed program, including test data, etc.: 40 308 No. of lines in distributed program, including test data, etc.: 5370 Distribution format:tar.gz Nature of physical problem: For a self-consistent description of nuclear pair correlations, both the particle–hole (field) and particle–particle (pairing) channels of the nuclear mean field must be treated within a common approach, which is the Hartree–Fock–Bogolyubov theory. By expressing these fields in spatial coordinates one can obtain the best possible solutions of the problem; however, without assuming specific symmetries the numerical task is often too difficult. This is not the case when the spherical symmetry is assumed, because then the one-dimensional differential equations can be solved very efficiently. Although the spherically symmetric solutions are physically meaningful only for magic and semi-magic nuclei, the possibility of obtaining them within tens of seconds of the CPU makes them a valuable element for studying nuclei across the nuclear chart, including those near or at the drip lines. Method of solution: The program determines the two-component Hartree–Fock–Bogolyubov quasiparticle wave functions on the lattice of equidistant points in the radial coordinate. This is done by solving the eigensystem of two second-order differential equations using the Numerov method. A standard iterative procedure is then used to find self-consistent solutions for the nuclear product wave functions and densities. Restrictions on the complexity of the problem: The main restriction is related to the assumed spherical symmetry. Typical running time: One Hartree–Fock iteration takes about 0.4 s for a medium mass nucleus, convergence is achieved in about 40 s. Unusual features of the program: none