ℋ- EFTCAMB : a Cobaya-integrated, Python-wrapped extension of EFTCAMB for covariant Horndeski gravity

Journal of Cosmology and Astroparticle Physics, vol. 2026, pp. 041

Abstract

Abstract We present ℋ- EFTCAMB , the official successor to EFTCAMB . The original EFTCAMB is designed as a consistent and numerically stable implementation of the effective field theory (EFT) of dark energy in the Einstein-Boltzmann code CAMB . On top of this, ℋ- EFTCAMB introduces a new Horndeski module that supports computing cosmology for an arbitrary input covariant Horndeski Lagragian. ℋ- EFTCAMB supports both mapping the Horndeski theory to an EFT lagrangian to solve in the EFT framework as well as directly solving for the scalar field equations of motion derived from the covariant Lagrangian. The latter approach also works for the cases when the Horndeski field experiences turn-overs, e.g. oscillation, where the EFT approach breaks down. The Horndeski module has been validated by comparing internally with existing models in the original EFTCAMB and externally with hi_class . ℋ- EFTCAMB features a flexible Python wrapper that is seamlessly integrated into the widely utilized cosmological sampler Cobaya . ℋ- EFTCAMB is publicly available and serves as a comprehensive tool for testing gravity against the precision data from current and next-generation surveys. ℋ- EFTCAMB is publicly available at this URL .

Authors 9

1. Gen Ye Aachen Institute Lorentz

   University of Geneva · Leiden University · University of Chinese Academy of Sciences

   Affiliation as printed

   Département de Physique Théorique and Centre for Astroparticle Physics, Université de Genève, 24 quai Ernest-Ansermet, CH-1211 Genève 4,

   Institute Lorentz, Leiden University, PO Box 9506, Leiden 2300 RA,

   School of Physics, University of Chinese Academy of Sciences, Beijing 100049,

2. Shijie Lin

   Beijing Normal University

   Affiliation as printed

   Institute for Frontier in Astronomy and Astrophysics, Beijing Normal University, Beijing 102206,

   School of Physics and Astronomy, Beijing Normal University, Beijing 100875,

3. Jiaming Pan

   University of Michigan

   Affiliation as printed

   Department of Physics and Leinweber Institute for Theoretical Physics, University of Michigan, 450 Church St, Ann Arbor, MI 48109,

4. Dani de Boe Aachen Institute Lorentz

   Leiden University

   Affiliation as printed

   Institute Lorentz, Leiden University, PO Box 9506, Leiden 2300 RA,

5. Stan Verhoeve Aachen Institute Lorentz

   Leiden University

   Affiliation as printed

   Institute Lorentz, Leiden University, PO Box 9506, Leiden 2300 RA,

6. Marco Raveri

   Istituto Nazionale di Fisica Nucleare, Sezione di Genova · University of Genoa

   Affiliation as printed

   Department of Physics and INFN, University of Genova, Via Dodecaneso 33, 16146,

7. Bin Hu

   Beijing Normal University

   Affiliation as printed

   Institute for Frontier in Astronomy and Astrophysics, Beijing Normal University, Beijing 102206,

   School of Physics and Astronomy, Beijing Normal University, Beijing 100875,

8. Noemi Frusciante

   Istituto Nazionale di Fisica Nucleare, Sezione di Napoli · University of Naples Federico II

   Affiliation as printed

   Dipartimento di Fisica “E. Pancini”, Università degli Studi di Napoli “Federico II”, Compl. Univ. di Monte S. Angelo, Edificio G, Via Cinthia, I-80126, Napoli,

   INFN Sezione di Napoli, Università degli Studi di Napoli “Federico II”, Compl. Univ. di Monte S. Angelo, Edificio G, Via Cinthia, I-80126, Napoli,

9. Alessandra Silvestri Aachen Institute Lorentz

   Leiden University

   Affiliation as printed

   Institute Lorentz, Leiden University, PO Box 9506, Leiden 2300 RA,