modern_nn_potentials

Caveat (Feburary 1, 2025)

The code herein is the subject of an ongoing review in preparation for the finalization and submission of a new paper. Code appertaining to the already published Millican et al. (2024) paper (see below) is in a worthy state to be downloaded and run, but this cannot be said for other code. Once the code for the forthcoming 2025 paper is finalized, it will be pushed here as version 1.0 and this caveat will be deleted.

Accompanying works

This repository contains all code and data necessary to generate the results in Assessing Correlated Truncation Errors in Modern Nucleon-Nucleon Potentials (https://arxiv.org/abs/2402.13165) and another, follow-on paper to come in 2025.

Installation

• This project relies on python=3.8. It was not tested with different versions. To view the entire list of required packages, see environment.yml.
• Note that a LaTeX distribution (such as Miktex) is also necessary in order to render the figures.
• Clone the repository to your local machine.
• Once you have cd into this repo, create a virtual environment (assuming you have conda installed) via

conda env create -f environment.yaml

• Enter the virtual environment with conda activate modern-nn-potentials
• Install the cheftgp package in the repo root directory using pip install -e . (you only need the -e option if you intend to edit the source code in cheftgp/).

Contents

Beginning with order-by-order predictions of nucleon-nucleon (NN) scattering observables generated using modern NN potentials that are implementations of chiral effective field theory ($\chi$EFT), this library extracts dimensionless coefficients according to the BUQEYE model.

• Data for 12 potentials is found in observables_data.

From here, one can plot the resulting coefficients and test how well they are described as random draws from the same Gaussian process (GP) using statistical diagnostics.

• To generate the figures found in Assessing Correlated Truncation Errors in Modern Nucleon-Nucleon Potentials, run notebooks/figures1.ipynb.
• To generate the figures found in the forthcoming 2025 paper, run notebooks/figures2.ipynb.

Additionally, one can evaluate the posterior probability distribution functions for parameters of the theory such as the breakdown momentum scale $\Lambda_{b}$ and the soft scale $m_{\mathrm{eff}}$.

• To generate the values of these parameters in Assessing Correlated Truncation Errors in Modern Nucleon-Nucleon Potentials's Table III, run scripts/posteriors_script_tab3_x.py (with x replacing the number of the row of interest in that table).
• Accompanying data files are included in scripts/data.

Miscellaneous

Unit tests can be found in tests/unit_tests.ipynb.

Citing this work

Please cite this work as follows:

@misc{millican2024assessing,
      title={Assessing Correlated Truncation Errors in Modern Nucleon-Nucleon Potentials}, 
      author={P. J. Millican and R. J. Furnstahl and J. A. Melendez and D. R. Phillips and M. T. Pratola},
      year={2024},
      eprint={2402.13165},
      archivePrefix={arXiv},
      primaryClass={nucl-th}
}