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Main Authors: Liu, Wenzhong, Wu, Yabo, Pan, Supriya, Yang, Weiqiang
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2507.09258
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author Liu, Wenzhong
Wu, Yabo
Pan, Supriya
Yang, Weiqiang
author_facet Liu, Wenzhong
Wu, Yabo
Pan, Supriya
Yang, Weiqiang
contents Astronomical observations suggest that the current standard $Λ$-Cold Dark Matter model in modern cosmology has some discrepancies when fitting the data during the whole expansion history of the universe. To solve the Hubble constant ($H_0$) tension, usually an unknown mechanism is considered that shifts the sound horizon at the decoupling era. On the other hand, dynamical dark energy models are also considered to resolve the problems of the cosmological constant, and the additional degrees of freedom require initial conditions for a solution. In this article we have considered a coupled quintessence dark energy model with a special focus on its early-time behaviour. In our solution the initial conditions are naturally decided by setting the value of the sound horizon at the recombination time, $θ^*$. We find that during this process, $H_0$ could be derived and its value rises with the coupling strength of the interaction. We also performed the background and cosmic microwave background power spectrum analysis, and find that the existence of the interaction term affects the energy density during a narrow time interval range and shifts the early cosmic microwave background spectrum. We also constrained the parameter space of the underlying scenario using the markov chain monte carlo analysis. We find that the best-fit values of $H_0$ and $S_8$ are improved slightly for the interacting model, but not enough to release the tensions.
format Preprint
id arxiv_https___arxiv_org_abs_2507_09258
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Solving an Interacting Quintessence Model with a Sound Horizon Initial Condition and its Observational Constraints
Liu, Wenzhong
Wu, Yabo
Pan, Supriya
Yang, Weiqiang
General Relativity and Quantum Cosmology
Astronomical observations suggest that the current standard $Λ$-Cold Dark Matter model in modern cosmology has some discrepancies when fitting the data during the whole expansion history of the universe. To solve the Hubble constant ($H_0$) tension, usually an unknown mechanism is considered that shifts the sound horizon at the decoupling era. On the other hand, dynamical dark energy models are also considered to resolve the problems of the cosmological constant, and the additional degrees of freedom require initial conditions for a solution. In this article we have considered a coupled quintessence dark energy model with a special focus on its early-time behaviour. In our solution the initial conditions are naturally decided by setting the value of the sound horizon at the recombination time, $θ^*$. We find that during this process, $H_0$ could be derived and its value rises with the coupling strength of the interaction. We also performed the background and cosmic microwave background power spectrum analysis, and find that the existence of the interaction term affects the energy density during a narrow time interval range and shifts the early cosmic microwave background spectrum. We also constrained the parameter space of the underlying scenario using the markov chain monte carlo analysis. We find that the best-fit values of $H_0$ and $S_8$ are improved slightly for the interacting model, but not enough to release the tensions.
title Solving an Interacting Quintessence Model with a Sound Horizon Initial Condition and its Observational Constraints
topic General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2507.09258