The gradient expansion formalism factory (GEFF)

This python package is designed to handle gauge-field production during cosmic inflation using the gradient expansion formalism (GEF).

With this package, the user has access to built-in and ready-to-use models to determine the dynamical evolution during axion inflation. Furthermore, the GEFF package allows you to create your own versions of inflationary models featuring gauge-field production, which can be solved using the GEF technique.

For more information on the GEFF, please see our documentation, and our arXiv manual

Installation

To install this package use

pip install cosmo-geff

or use the geff.yml file to create a conda environment,

conda env create -f geff.yml

Attribution

If you use this software in your work, please cite:

von Eckardstein, R. (2025). GEFF: The Gradient Expansion Formalism Factory. Zenodo. https://doi.org/10.5281/zenodo.17356579

@misc{von_eckardstein_2025_17356579,
  author       = {von Eckardstein, Richard},
  title        = {GEFF: The Gradient Expansion Formalism Factory},
  month        = oct,
  year         = 2025,
  publisher    = {Zenodo},
  doi          = {10.5281/zenodo.17356579},
  url          = {https://doi.org/10.5281/zenodo.17356579},
}

von Eckardstein, R. (2025). GEFF: The Gradient Expansion Formalism Factory - A tool for inflationary gauge-field production. arXiv. https://arxiv.org/abs/2510.12644

@misc{vonEckardstein:2025jug,
    author        = {von Eckardstein, Richard},
    title         = {GEFF: The Gradient Expansion Formalism Factory - A tool for inflationary gauge-field production},
    eprint        = {2510.12644},
    archivePrefix = {arXiv},
    primaryClass  = {astro-ph.CO},
    reportNumber  = {MS-TP-25-37},
    month         = oct,
    year          = 2025
}