Any unified early and late dark energy scenario with a single tracking scalar field requires a potential with three distinct slopes arranged in a steep-steeper-shallow hierarchy.
Canonical reference
Tale of stable interacting dark energy, observational signatures, and the $H_0$ tension
Canonical reference. 90% of citing Pith papers cite this work as background.
abstract
We investigate the observational consequences of a novel class of stable interacting dark energy (IDE) models, featuring interactions between dark matter (DM) and dark energy (DE). In the first part of our work, we start by considering two IDE models which are known to present early-time linear perturbation instabilities. Applying a transformation depending on the dark energy equation of state (EoS) to the DM-DE coupling, we then obtain two novel stable IDE models. Subsequently, we derive robust and accurate constraints on the parameters of these models, assuming a constant EoS $w_x$ for the DE fluid, in light of some of the most recent publicly available cosmological data. These include Cosmic Microwave Background (CMB) temperature and polarization anisotropy measurements from the \textit{Planck} satellite, a selection of Baryon Acoustic Oscillation measurements, Supernovae Type-Ia luminosity distance measurements from the JLA sample, and measurements of the Hubble parameter up to redshift $2$ from cosmic chronometers. Our analysis displays a mild preference for the DE fluid residing in the phantom region ($w_x<-1$), with significance up to 95\% confidence level, while we obtain new upper limits on the coupling parameter between the dark components. The preference for a phantom DE suggests a coupling function $Q<0$, thus a scenario where energy flows from the DE to the DM. We also examine the possibility of addressing the $H_0$ and $\sigma_8$ tensions, finding that only the former can be partially alleviated. Finally, we perform a Bayesian model comparison analysis to quantify the possible preference for the two IDE models against the standard concordance $\Lambda$CDM model, finding that the latter is always preferred with the strength of the evidence ranging from positive to very strong.
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Two-field axion-like early dark energy reduces Hubble tension to 1.5 sigma residual and improves high-ell CMB fits over single-field models.
EDE models increase inferred α_s from CMB data, strengthening tension with USR PBH models that predict negative running.
Evidence for dynamical dark energy in the w0waCDM framework is strongly dataset-dependent, driven by mismatches in low-redshift BAO distance ratios that produce divergent expansion histories and inconsistent Hubble tension relief.
Exponential IR f(T) gravity Model I alleviates Hubble tension but is disfavoured by combined Planck/ACT/SPT+DESI+Pantheon+ data; Model II is ruled out because background constraints force unphysical shifts in CMB parameters.
Upper bounds on total neutrino mass in four phenomenological interacting dark energy models are derived from DESI DR2 BAO plus CMB and SNIa data, showing strong dependence on the interaction term form and statistical preference for models that tighten the bound below the oscillation lower limit.
Models of interacting bosonic dark energy and fermionic dark matter in Einstein-scalar-Gauss-Bonnet gravity with exponential and power-law potentials are dynamically analyzed and constrained by observational data, showing consistency with LambdaCDM.
This review traces the history of dynamical dark energy, presents the no-go theorem against single-field crossing of w = -1, and surveys viable Quintom constructions including multi-field models and modified gravity in light of DESI DR2 hints.
A review summarizing advancements over the past two years that link DESI baryon acoustic oscillation data to string-inspired scenarios with dynamic dark energy.
citing papers explorer
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Unifying Early and Late Dark Energy: Dynamical Requirements and Obstructions
Any unified early and late dark energy scenario with a single tracking scalar field requires a potential with three distinct slopes arranged in a steep-steeper-shallow hierarchy.
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Geometric Constraints on the Pre-Recombination Expansion History from the Hubble Tension
Model-independent reconstruction shows that early-universe modifications resolving the Hubble tension exist at the background level, requiring a smooth ~15% pre-recombination expansion rate enhancement.
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Double the axions, half the tension: multi-field early dark energy eases the Hubble tension
Two-field axion-like early dark energy reduces Hubble tension to 1.5 sigma residual and improves high-ell CMB fits over single-field models.
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Running into tension: primordial black holes from ultra-slow-roll inflation, spectral running, and the Hubble tension
EDE models increase inferred α_s from CMB data, strengthening tension with USR PBH models that predict negative running.
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Probing Dynamical Dark Energy with Late-Time Data: Evidence, Tensions, and the Limits of the $w_0w_a$CDM Framework
Evidence for dynamical dark energy in the w0waCDM framework is strongly dataset-dependent, driven by mismatches in low-redshift BAO distance ratios that produce divergent expansion histories and inconsistent Hubble tension relief.
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Cosmological Viability of Exponential Infrared $f(T)$ Gravity
Exponential IR f(T) gravity Model I alleviates Hubble tension but is disfavoured by combined Planck/ACT/SPT+DESI+Pantheon+ data; Model II is ruled out because background constraints force unphysical shifts in CMB parameters.
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Neutrino mass constraints in interacting dark energy models after DESI DR2
Upper bounds on total neutrino mass in four phenomenological interacting dark energy models are derived from DESI DR2 BAO plus CMB and SNIa data, showing strong dependence on the interaction term form and statistical preference for models that tighten the bound below the oscillation lower limit.
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Breaking Free from the Swampland of Impossible Universes through the DESI Portal
A review summarizing advancements over the past two years that link DESI baryon acoustic oscillation data to string-inspired scenarios with dynamic dark energy.