2019/09/30 by Emilio Bellini, Ignacy Sawicki, Miguel Zumalacárregui · 63 citations
Physics and Astronomy · #Adiabatic process #Code (set theory) #Cosmology #Cosmology and Gravitation Theories #Covariant transformation #Dark energy #Energy (signal processing) #Galaxies: Formation, Evolution, Phenomena #Particle physics theoretical and experimental studies #Quasistatic process #Quintessence #Range (aeronautics) #astro-ph.CO #gr-qc #hep-ph #hep-th
paper · pdf · doi:10.1088/1475-7516/2020/02/008
published in Journal of Cosmology and Astroparticle Physics 2020(02), 008 (Institute of Physics) · 35 pages + appendices, 11 figures. Updated discussions. Code available on https://github.com/miguelzuma/hi_class_public
openalex created_date 2019/09/12 · openalex publication_date 2020/02/10 · arxiv created 2020/02/11 · arxiv updated 2020/02/13 · openalex updated_date 2026/08/05
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 hiclass ( 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 hiclass : (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 quasi-static 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 ΛCDM cosmologies. The hiclass code is publicly available ( https://github.com/miguelzuma/hiclasspublic ), ready to explore current data and prepare for next-generation experiments.