Cosmic backreaction and the mean redshift drift from symbolic regression
arXiv:2305.01223 · doi:10.1103/PhysRevD.107.103522
Abstract
The possibility of obtaining symbolic expressions for cosmic backreaction is explored through a case study of so-called 2-region models. By using the publicly available symbolic regression algorithm AI Feynman, it is shown that the kinematical backreaction from a single 2-region model can be well described as a function of the mean redshift (or, equivalently, the volume averaged scale factor). A single expression depending on the redshift/scale factor as well as a model parameter, , that can accurately describe the backreaction for a significant range of models is naturally more complicated but is also achieved with percent-level accuracy. \newline\indent Data sets of redshift drift in the 2-region models are also considered. Again utilizing AI Feynman, expressions for the redshift drift are found. In particular, an expression for the difference between the mean redshift drift and the drift of the mean redshift in terms of the kinematical backreaction is easily obtained for a single 2-region model. An accurate symbolic expression that describes this difference for an array of 2-region models is achieved by using the redshift as a feature instead of the kinematical backreaction.
20 pages incl. 16 captioned figures. Accepted for publication in PRD. v2: Updated bibliography. No other changes
References in corpus (31)
- Cosmic dynamics in the era of Extremely Large Telescopes
- Exact solution to the averaging problem in cosmology
- On cosmological observables in a swiss-cheese universe
- Accelerated expansion from structure formation
- Correspondence between kinematical backreaction and scalar field cosmologies - the `morphon field'
- Light-cone averages in a swiss-cheese universe
- Multiscale cosmology and structure-emerging Dark Energy: A plausibility analysis
- Szekeres Swiss-Cheese model and supernova observations
- On the onset of cosmological backreaction
- On the curvature of the present-day Universe
- The Szekeres Swiss Cheese model and the CMB observations
- Luminosity distance in "Swiss cheese" cosmology with randomized voids: I. Single void size
- Backreaction on the luminosity-redshift relation from gauge invariant light-cone averaging
- Observable Deviations from Homogeneity in an Inhomogeneous Universe
- Redshift Drift in LTB Void Universes
- Swiss Cheese and a Cheesy CMB
- Another look at redshift drift and the backreaction conjecture
- Ricci focusing, shearing, and the expansion rate in an almost homogeneous Universe
- Light propagation in a homogeneous and anisotropic universe
- Local and non-local measures of acceleration in cosmology
- Redshift propagation equations in the Szekeres models
- Cosmological acceleration from structure formation
- Weak gravitational lensing of finite beams
- Redshift drift in axially symmetric quasi-spherical Szekeres models
- Generalized covariant prescriptions for averaging cosmological observables
- Analytical Estimate of the Effect of Spherical Inhomogeneities on Luminosity Distance and Redshift
- Multipole decomposition of redshift drift -- model independent mapping of the expansion history of the Universe
- Redshift drift in a pressure-gradient cosmology
- Machine learning cosmic backreaction and its effects on observations
- Quantifying effects of inhomogeneities and curvature on gravitational wave standard siren measurements of
- Redshift drift in a universe with structure II: Light rays propagated through a Newtonian N-body simulation