hi_class background evolution, initial conditions and approximation schemes

0540705 - FZÚ 2021 RIV GB eng J - Journal Article
Bellini, E. - Sawicki, Ignacy - Zumalacarregui, M.
hi_class background evolution, initial conditions and approximation schemes.
Journal of Cosmology and Astroparticle Physics. Roč. 2020, č. 2 (2020), s. 1-52, č. článku 008. ISSN 1475-7516. E-ISSN 1475-7516
R&D Projects: GA MŠMT EF15_003/0000437
Grant - others:OP VVV - CoGraDS(XE) CZ.02.1.01/0.0/0.0/15_003/0000437
Institutional support: RVO:68378271
Keywords : field theory: scalar * isocurvature: perturbation * gravitation: model
OECD category: Atomic, molecular and chemical physics (physics of atoms and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect)
Impact factor: 5.839, year: 2020
Method of publishing: Limited access
https://doi.org/10.1088/1475-7516/2020/02/008

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.

Permanent Link: http://hdl.handle.net/11104/0318325