A finite-temperature Hartree–Fock code for shell-model Hamiltonians

The codes HFgradZ.py and HFgradT.py find axially symmetric minima of a Hartree–Fock energy functional for a Hamiltonian supplied in a shell model basis. The functional to be minimized is the Hartree–Fock energy for zero-temperature properties or the Hartree–Fock grand potential for finite-temperature properties (thermal energy, entropy). The minimization may be subjected to additional constraints besides axial symmetry and nucleon numbers. A single-particle operator can be used to constrain the minimization by adding it to the single-particle Hamiltonian with a Lagrange multiplier. One can also constrain its expectation value in the zero-temperature code. Also the orbital filling can be constrained in the zero-temperature code, fixing the number of nucleons having given KπKπ quantum numbers. This is particularly useful to resolve near-degeneracies among distinct minima.