A Dynamical Scalar Field Model for Dark Energy: Addressing the Hubble Tension and Cosmic Evolution
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| Format: | Preprint |
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2025
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| author | Kottur, Arpit Mahajan, Jui Dabhade, Raka |
| author_facet | Kottur, Arpit Mahajan, Jui Dabhade, Raka |
| contents | We propose a dynamical dark energy model based on a canonical scalar field with a hybrid potential of the form $V(ϕ) = V_{0}e^{-λϕ} + V_{1}ϕ^{n}$. We constrain the model's 11-dimensional parameter space using a comprehensive combination of cosmological data, including the Planck 2018 Cosmic Microwave Background (CMB) power spectra, Baryon Acoustic Oscillations (BAO), the Pantheon+ supernova sample, SH0ES and the matter power spectrum from SDSS. The model provides an excellent fit to the data, with a reduced chi-squared of $χ^2_{\text{red}} = 0.989$, while successfully alleviating the Hubble constant tension. Our analysis yields a Hubble constant of $H_0 \approx 72.820$ km/s/Mpc, reducing the discrepancy between early and late-universe measurements. We find that the data favors a 'thawing' quintessence scenario, characterized by a potential slope parameter $λ\approx 0.056$. This small but non-zero slope drives a late-time deviation from $Λ$CDM ($w(z=0) \approx -0.85$) while preserving the standard expansion history at high redshifts. A model comparison using the Bayesian Information Criterion finds that the standard $Λ$CDM model is still slightly preferred ($Δ\text{BIC} = 2.178$) due to its fewer parameters. Nevertheless, our results demonstrate that this hybrid potential model is a compelling, physically motivated alternative to a cosmological constant. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2511_10317 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | A Dynamical Scalar Field Model for Dark Energy: Addressing the Hubble Tension and Cosmic Evolution Kottur, Arpit Mahajan, Jui Dabhade, Raka Cosmology and Nongalactic Astrophysics We propose a dynamical dark energy model based on a canonical scalar field with a hybrid potential of the form $V(ϕ) = V_{0}e^{-λϕ} + V_{1}ϕ^{n}$. We constrain the model's 11-dimensional parameter space using a comprehensive combination of cosmological data, including the Planck 2018 Cosmic Microwave Background (CMB) power spectra, Baryon Acoustic Oscillations (BAO), the Pantheon+ supernova sample, SH0ES and the matter power spectrum from SDSS. The model provides an excellent fit to the data, with a reduced chi-squared of $χ^2_{\text{red}} = 0.989$, while successfully alleviating the Hubble constant tension. Our analysis yields a Hubble constant of $H_0 \approx 72.820$ km/s/Mpc, reducing the discrepancy between early and late-universe measurements. We find that the data favors a 'thawing' quintessence scenario, characterized by a potential slope parameter $λ\approx 0.056$. This small but non-zero slope drives a late-time deviation from $Λ$CDM ($w(z=0) \approx -0.85$) while preserving the standard expansion history at high redshifts. A model comparison using the Bayesian Information Criterion finds that the standard $Λ$CDM model is still slightly preferred ($Δ\text{BIC} = 2.178$) due to its fewer parameters. Nevertheless, our results demonstrate that this hybrid potential model is a compelling, physically motivated alternative to a cosmological constant. |
| title | A Dynamical Scalar Field Model for Dark Energy: Addressing the Hubble Tension and Cosmic Evolution |
| topic | Cosmology and Nongalactic Astrophysics |
| url | https://arxiv.org/abs/2511.10317 |