Probing late-time deviations from $Λ$CDM with a quadratic dark energy expansion
Fuente:
arXiv
Guardado en:
| Autores principales: | , , , |
|---|---|
| Formato: | Preprint |
| Publicado: |
2026
|
| Materias: | |
| Acceso en línea: | |
| Etiquetas: |
Agregar Etiqueta
Sin Etiquetas, Sea el primero en etiquetar este registro!
|
| _version_ | 1866914582011838464 |
|---|---|
| author | Khandelwal, Sehjal Capistrano, Abraão J. S. Kumar, Suresh Nunes, Rafael C. |
| author_facet | Khandelwal, Sehjal Capistrano, Abraão J. S. Kumar, Suresh Nunes, Rafael C. |
| contents | We investigate the observational viability of a quadratic dark energy expansion (QDEE) model as a phenomenological extension of the standard $Λ\mathrm{CDM}$ cosmological framework. This approach introduces the additional degrees of freedom that permit mild late-time deviations from a constant dark-energy component while preserving the standard early-Universe behavior. We constrain the model using a comprehensive combination of cosmological datasets, including Planck 2018 cosmic microwave background (CMB) measurements, Atacama Cosmology Telescope (ACT) Data Release 6 (DR6) and South Pole Telescope (SPT-3G) data, Dark Energy Spectroscopic Instrument (DESI) Data Release 2 (DR2), and the Pantheon Plus type Ia supernova compilation. Our results show that the QDEE framework shifts the inferred Hubble constant toward higher values relative to $Λ\mathrm{CDM}$, partially alleviating the tension with local measurements while remaining consistent with early-Universe constraints. Bayesian model comparison indicates strong evidence in favor of this framework over standard $Λ\mathrm{CDM}$ across multiple dataset combinations. Posterior predictive checks further demonstrate that the model yields predictions consistent with the observed data within statistical uncertainties. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2605_20748 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Probing late-time deviations from $Λ$CDM with a quadratic dark energy expansion Khandelwal, Sehjal Capistrano, Abraão J. S. Kumar, Suresh Nunes, Rafael C. Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology We investigate the observational viability of a quadratic dark energy expansion (QDEE) model as a phenomenological extension of the standard $Λ\mathrm{CDM}$ cosmological framework. This approach introduces the additional degrees of freedom that permit mild late-time deviations from a constant dark-energy component while preserving the standard early-Universe behavior. We constrain the model using a comprehensive combination of cosmological datasets, including Planck 2018 cosmic microwave background (CMB) measurements, Atacama Cosmology Telescope (ACT) Data Release 6 (DR6) and South Pole Telescope (SPT-3G) data, Dark Energy Spectroscopic Instrument (DESI) Data Release 2 (DR2), and the Pantheon Plus type Ia supernova compilation. Our results show that the QDEE framework shifts the inferred Hubble constant toward higher values relative to $Λ\mathrm{CDM}$, partially alleviating the tension with local measurements while remaining consistent with early-Universe constraints. Bayesian model comparison indicates strong evidence in favor of this framework over standard $Λ\mathrm{CDM}$ across multiple dataset combinations. Posterior predictive checks further demonstrate that the model yields predictions consistent with the observed data within statistical uncertainties. |
| title | Probing late-time deviations from $Λ$CDM with a quadratic dark energy expansion |
| topic | Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology |
| url | https://arxiv.org/abs/2605.20748 |