From Scalar $H_0$ to $E(z)$: A Reformulation of the Hubble Tension
Fuente:
arXiv
Enregistré dans:
| Auteur principal: | |
|---|---|
| Format: | Preprint |
| Publié: |
2026
|
| Sujets: | |
| Accès en ligne: | |
| Tags: |
Ajouter un tag
Pas de tags, Soyez le premier à ajouter un tag!
|
| _version_ | 1866910196032339968 |
|---|---|
| author | Lee, Seokcheon |
| author_facet | Lee, Seokcheon |
| contents | The Hubble tension is usually expressed as a discrepancy between the low H_0 inferred from Planck CMB data within base \LambdaCDM and the higher value obtained from late-time distance-ladder measurements. This scalar comparison compresses distinct inference problems into one derived parameter: Planck CMB, DESI DR2 BAO, and Pantheon+SH0ES constrain physical densities and acoustic scales, ruler-normalized distances, and calibrated luminosity-distance relations, respectively. We reformulate the comparison in terms of the dimensionless expansion history E(z)=H(z)/H_0. This does not remove the absolute-scale discrepancy, but separates the normalization encoded in $H_0$ from the redshift-dependent shape of the expansion history. Within a common flat-\LambdaCDM framework, each probe posterior is mapped onto posterior-implied E(z) histories. Since the reconstructed values E(z_k) are strongly correlated across redshift, we quantify the global mismatch with a covariance-subspace history displacement S_{hist}, alongside pointwise redshift differences. The histories are not identical, but the discrepancies are moderate: the pointwise significance is typically 1-2σ, while S_{hist} simeq 1.65 for DESI DR2 and S_{hist} \simeq 2.55 for Pantheon+SH0ES relative to Planck. With two retained covariance eigenmodes, these correspond to two-sided one-dimensional Gaussian equivalents of approximately 1.1σand 2.1σ, both below the conventional \simeq 4.9σPlanck-SH0ES scalar-H_0 discrepancy. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2605_05691 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | From Scalar $H_0$ to $E(z)$: A Reformulation of the Hubble Tension Lee, Seokcheon Cosmology and Nongalactic Astrophysics The Hubble tension is usually expressed as a discrepancy between the low H_0 inferred from Planck CMB data within base \LambdaCDM and the higher value obtained from late-time distance-ladder measurements. This scalar comparison compresses distinct inference problems into one derived parameter: Planck CMB, DESI DR2 BAO, and Pantheon+SH0ES constrain physical densities and acoustic scales, ruler-normalized distances, and calibrated luminosity-distance relations, respectively. We reformulate the comparison in terms of the dimensionless expansion history E(z)=H(z)/H_0. This does not remove the absolute-scale discrepancy, but separates the normalization encoded in $H_0$ from the redshift-dependent shape of the expansion history. Within a common flat-\LambdaCDM framework, each probe posterior is mapped onto posterior-implied E(z) histories. Since the reconstructed values E(z_k) are strongly correlated across redshift, we quantify the global mismatch with a covariance-subspace history displacement S_{hist}, alongside pointwise redshift differences. The histories are not identical, but the discrepancies are moderate: the pointwise significance is typically 1-2σ, while S_{hist} simeq 1.65 for DESI DR2 and S_{hist} \simeq 2.55 for Pantheon+SH0ES relative to Planck. With two retained covariance eigenmodes, these correspond to two-sided one-dimensional Gaussian equivalents of approximately 1.1σand 2.1σ, both below the conventional \simeq 4.9σPlanck-SH0ES scalar-H_0 discrepancy. |
| title | From Scalar $H_0$ to $E(z)$: A Reformulation of the Hubble Tension |
| topic | Cosmology and Nongalactic Astrophysics |
| url | https://arxiv.org/abs/2605.05691 |