Pith. sign in

REVIEW 7 cited by

hi_class: Background Evolution, Initial Conditions and Approximation Schemes

Not yet reviewed by Pith; the record is open.

This paper has not been read by Pith yet. Machine review is queued; the pith claim, tier, and objections will appear here once it completes.

SPECIMEN: schema-true, not a live event

T0 review · schema-true

One-sentence machine reading of the paper's core claim.

pith:XXXXXXXX · record.json · timestamp

arxiv 1909.01828 v3 pith:YX2PJMI2 submitted 2019-09-04 astro-ph.CO gr-qchep-phhep-th

classification astro-ph.COgr-qchep-phhep-th
keywords classconditionsdarkenergymodelsapproximationavailablebackground
verification ladder T0 review T1 audit T2 compute T3 formal
0 comments
abstract

Cosmological datasets have great potential to elucidate the nature of dark energy and test gravity on the largest scales available to observation. Theoretical predictions can be computed with hi_class (www.hiclass-code.net), an accurate, fast and flexible code for linear cosmology, incorporating a wide range of dark energy theories and modifications to general relativity. We introduce three new functionalities into hi_class: (1) Support for models based on covariant Lagrangians, including a constraint-preserving integration scheme for the background evolution and a series of worked-out examples: Galileon, nKGB, quintessence (monomial, tracker) and Brans-Dicke. (2) Consistent initial conditions for the scalar-field perturbations in the deep radiation era, identifying the conditions under which modified-gravity isocurvature perturbations may grow faster than adiabatic modes leading to a loss of predictivity. (3) An automated quasistatic approximation scheme allowing order-of-magnitude improvement in computing performance without sacrificing accuracy for wide classes of models. These enhancements bring the treatment of dark energy and modified gravity models to the level of detail comparable to software tools restricted to standard $\Lambda$CDM cosmologies. The hi_class code is publicly available (https://github.com/miguelzuma/hi_class_public), ready to explore current data and prepare for next-generation experiments.

Discussion (0). Continue with ORCID to comment.

Forward citations

Cited by 7 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score. Full citation record

  1. Nonlinear reconstruction of general dark energy theories

    astro-ph.CO 2025-07 conditional novelty 6.0 of 10

    A reconstruction method is derived that turns background expansion and linear perturbation data into full non-linear Lagrangians for quintessence, scalar-tensor, k-essence, and shift-symmetric cubic Galileon dark ener...

  2. EFT-Ramses: a code to simulate the effective field theory of dark energy

    astro-ph.CO 2026-07 accept novelty 5.5 of 10

    A unified AMR N-body code embeds EFTofDE α-basis models into one master Vainshtein equation and matches legacy ECOSMOG and HiCOLA matter power spectra.

  3. Signatures of kinetic gravity braiding in cosmological probes of the gravitational field

    gr-qc 2026-07 accept novelty 5.0 of 10

    KGB braiding boosts weak-lensing power by ~10–12% at ℓ~10²–10³ and flips the ISW–RS difference from suppression to excess once nonlinear Rees–Sciama physics dominates.

  4. Robustness of dark energy phenomenology across different parameterizations

    astro-ph.CO 2025-02 conditional novelty 5.0 of 10

    The viability of minimally and non-minimally coupled quintessence models is robust across CPL, JBP, BA, and EXP parameterizations, with all four reproducing the models' predicted observables accurately.

  5. Exploring cosmological imprints of phantom crossing with dynamical dark energy in Horndeski gravity

    astro-ph.CO 2024-12 conditional novelty 5.0 of 10

    A Horndeski scalar-field dark energy model that crosses the phantom divide and has negative early-time energy density fits cosmological data as well as LambdaCDM but does not resolve the main tensions.

  6. The Status of Single Scalar Field Dark Energy

    astro-ph.CO 2026-07 conditional novelty 4.5 of 10

    Cosmological data can constrain only a handful of EFT parameters for single-scalar dark energy; extended models show modest preference over Λ but remain underdetermined and challenged by fifth forces and screening.

  7. Cosmic Structure Formation in the Non-linear Regime: Beyond Gaussian Statistics and Standard Cosmologies

    astro-ph.CO 2024-11 conditional novelty 4.0 of 10

    The matter density PDF can be predicted in extended cosmologies with large deviations theory, and wave-based forward models capture phase-space dynamics beyond the fluid approximation.

Pith tools