NuHamil : A numerical code to generate nuclear two- and three-body matrix elements from chiral effective field theory

Area of Science:

• Nuclear physics
• Computational physics
• Quantum many-body theory

Background:

• Nuclear ab initio calculations are powerful but require significant numerical expertise.
• Generating nuclear interaction matrix elements and performing many-body calculations are key challenges for new researchers.

Purpose of the Study:

• Introduce NuHamil, a novel code designed to streamline the generation of nuclear interaction matrix elements.
• Facilitate the input for advanced many-body calculations in nuclear structure.

Main Methods:

• The NuHamil code generates nucleon-nucleon (NN) and three-nucleon (3N) matrix elements in a spherical harmonic-oscillator basis.
• Calculations utilize modern Fortran with OpenMP+MPI for parallelization.
• Ground-state energies of doubly closed shell nuclei are computed using no-core shell-model (NCSM) and in-medium similarity renormalization group (IMSRG) methods.

Main Results:

• Successfully generated NN and 3N matrix elements for nuclear structure calculations.
• Calculated ground-state energies for selected nuclei using NCSM and IMSRG.

Conclusions:

• NuHamil significantly lowers the barrier to entry for ab initio nuclear structure research.
• The code provides essential inputs for sophisticated many-body techniques, advancing nuclear theory development.