Derivation of the Background Expansion HB(z) in B-Space Cosmology
Fuente:
Zenodo
Enregistré dans:
| Auteur principal: | |
|---|---|
| Format: | Recurso digital |
| Publié: |
Zenodo
2025
|
| Sujets: | |
| Accès en ligne: | |
| Tags: |
Ajouter un tag
Pas de tags, Soyez le premier à ajouter un tag!
|
| _version_ | 1866902184386363392 |
|---|---|
| author | Shrourou, Firas |
| author_facet | Shrourou, Firas |
| contents | <p>This companion paper to the B-Space Cosmology foundation work derives the background expansion history HB(z) used across the project. It isolates late-time kinematics into a single constant rate F0 and provides the full pathway from definitions to observables.</p> <p>The paper includes:<br>• An exact “dust-limit” solution with closed-form expressions for HB(z), the flip redshift z_flip (onset of acceleration), and the age t0.<br>• The general baryons + radiation + switch ordinary differential equation (ODE) for HB(z), suitable for numerical integration and direct use in analyses.<br>• Two lawful, non-circular calibration routes for F0 (flip-based using z_flip, and age-based using t0), illustrated with Planck-2018 baselines.<br>• Distance relations (DC, DL, DA) in the standard Euclidean form so existing BAO, supernova, and cosmic-chronometer pipelines can be applied without modification.<br>• A practical note on photon escape: any small optical-depth term is handled in observables (supernova flux) and does not alter the background equations.<br>• A position statement on G-Drag (Γ0): background-neutral by construction; its effects live in growth/thermal sectors, not in HB(z).<br>• A reproducibility checklist (unit conventions, constants, switch parameterization) and a minimal code sketch for integrating the ODE and computing distances.</p> <p>Numerical examples show how a single calibrated F0 (e.g., via z_flip ≈ 0.7 or age t0 ≈ 13.8 Gyr) fixes the entire late-time background, while remaining fully comparable to standard LambdaCDM analyses (e.g., Planck-2018 typically places the transition near z_t ≈ 0.63). The emphasis is on transparent formulas, portable methods, and compatibility with mainstream datasets and tools.</p> <p>Designed to be a citable reference for all subsequent B-Space studies, this supplement bridges the main framework and day-to-day research use: one dial (F0), clear calibrations, and drop-in equations for distance calculations.</p> <p>Foundation paper (context):<br>Shrourou, F. (2025). B-Space Cosmology: Main Framework. Zenodo. <a href="https://doi.org/10.5281/zenodo.17069443" target="_new" rel="noopener">https://doi.org/10.5281/zenodo.17069443</a></p> <p>Keywords: B-Space Cosmology; background expansion; HB(z); F0 calibration; flip redshift; LambdaCDM mapping; BAO/SN/chronometers; Planck 2018; reproducibility.</p> |
| format | Recurso digital |
| id | zenodo_https___doi_org_10_5281_zenodo_17094340 |
| institution | Zenodo |
| language | |
| publishDate | 2025 |
| publisher | Zenodo |
| record_format | zenodo |
| spellingShingle | Derivation of the Background Expansion HB(z) in B-Space Cosmology Shrourou, Firas Physical cosmology <p>This companion paper to the B-Space Cosmology foundation work derives the background expansion history HB(z) used across the project. It isolates late-time kinematics into a single constant rate F0 and provides the full pathway from definitions to observables.</p> <p>The paper includes:<br>• An exact “dust-limit” solution with closed-form expressions for HB(z), the flip redshift z_flip (onset of acceleration), and the age t0.<br>• The general baryons + radiation + switch ordinary differential equation (ODE) for HB(z), suitable for numerical integration and direct use in analyses.<br>• Two lawful, non-circular calibration routes for F0 (flip-based using z_flip, and age-based using t0), illustrated with Planck-2018 baselines.<br>• Distance relations (DC, DL, DA) in the standard Euclidean form so existing BAO, supernova, and cosmic-chronometer pipelines can be applied without modification.<br>• A practical note on photon escape: any small optical-depth term is handled in observables (supernova flux) and does not alter the background equations.<br>• A position statement on G-Drag (Γ0): background-neutral by construction; its effects live in growth/thermal sectors, not in HB(z).<br>• A reproducibility checklist (unit conventions, constants, switch parameterization) and a minimal code sketch for integrating the ODE and computing distances.</p> <p>Numerical examples show how a single calibrated F0 (e.g., via z_flip ≈ 0.7 or age t0 ≈ 13.8 Gyr) fixes the entire late-time background, while remaining fully comparable to standard LambdaCDM analyses (e.g., Planck-2018 typically places the transition near z_t ≈ 0.63). The emphasis is on transparent formulas, portable methods, and compatibility with mainstream datasets and tools.</p> <p>Designed to be a citable reference for all subsequent B-Space studies, this supplement bridges the main framework and day-to-day research use: one dial (F0), clear calibrations, and drop-in equations for distance calculations.</p> <p>Foundation paper (context):<br>Shrourou, F. (2025). B-Space Cosmology: Main Framework. Zenodo. <a href="https://doi.org/10.5281/zenodo.17069443" target="_new" rel="noopener">https://doi.org/10.5281/zenodo.17069443</a></p> <p>Keywords: B-Space Cosmology; background expansion; HB(z); F0 calibration; flip redshift; LambdaCDM mapping; BAO/SN/chronometers; Planck 2018; reproducibility.</p> |
| title | Derivation of the Background Expansion HB(z) in B-Space Cosmology |
| topic | Physical cosmology |
| url | https://doi.org/10.5281/zenodo.17094340 |