REVIEW 11 cited by
Graduated dark energy: Observational hints of a spontaneous sign switch in the cosmological constant
Not yet reviewed by Pith; the record is open.
This paper has not been read by Pith yet. Machine review is queued; the pith claim, tier, and objections will appear here once it completes.
SPECIMEN: schema-true, not a live event
T0 review · schema-true
One-sentence machine reading of the paper's core claim.
pith:XXXXXXXX · record.json · timestamp
abstract
We study the cosmological constant ($\Lambda$) in the standard $\Lambda$CDM model by introducing the \textit{graduated dark energy} (gDE) characterised by a minimal dynamical deviation from the null inertial mass density of the $\Lambda$ in the form $\rho_{\rm inert}\propto \rho^{\lambda}<0$ with $\lambda<1$ being a ratio of two odd integers, for which its energy density $\rho$ dynamically takes negative values in the finite past. For large negative values of $\lambda$, it creates a phenomenological model described by a smooth function that approximately describes the $\Lambda$ spontaneously switching sign in the late universe to become positive today. We confront the model with the latest combined observational data sets of PLK+BAO+SN+$H$. It is striking that the data predict bimodal posterior probability distributions for the parameters of the model along with large negative $\lambda$ values; the new maximum significantly excludes the $\Lambda$, and the old maximum contains the $\Lambda$. The improvement in the goodness of fit for the $\Lambda$ reaches highly significant levels, $\Delta\chi_{\rm min}^2=6.4$ for the new maxima, while it remains at insignificant levels, $\Delta\chi_{\rm min}^2\lesssim0.02$, for the old maxima. We show that, in contrast to the old maxima, which do not distinguish from the $\Lambda$, the new maxima agree with the model-independent $H_0$ measurements, high-precision Ly-$\alpha$ data, and model-independent $Omh^2$ diagnostic estimates. Our results provide strong hints of a spontaneous sign switch in the cosmological constant and lead us to conjecture that the universe has transitioned from AdS vacua to dS vacua, at a redshift $z\approx 2.32$ and triggered the late-time acceleration, and suggests looking for such mechanisms in string theory constructions.
Forward citations
Cited by 11 Pith papers
-
Defocusing dark energy: Raychaudhuri diagnostics beyond $w<-1/3$ and the phantom divide
For sign-changing effective dark energy, smooth negative-to-positive density crossings make ρ+3p and ρ+p the correct diagnostics, give w=p/ρ a universal pole n(1+z†)/3, and force repulsion onset z_rep>z† while ρ<0.
-
Alleviating the Hubble Tension with Smooth Sign-Switching Dark Energy: Full CMB Constraints with DESI and PantheonPlus
Smooth ECDM dark energy remains compatible with Planck+ACT+SPT, DESI DR2 and Pantheon+/SH0ES while alleviating the Hubble tension through a controlled late-time density transition.
-
Background-level reconstruction of scalar-field potentials from dark-energy histories and comparison with analytic potential families
A background reconstruction maps prescribed ρ_de(z) histories to V(φ) and ranks analytic potentials by Bayesian evidence, with exponential preferred for CPL and shifted-tanh for sign-switching targets.
-
Endpoint Logarithms in the NLO Mueller-Navelet Jet Vertex: Threshold Matching and BLM/MOM Prescription Sensitivity
A conservative BFKL-aware threshold matching scheme is constructed for the NLO forward jet vertex that resums ordinary endpoint logs, preserves NLO accuracy, and is tested against CMS azimuthal observables, showing in...
-
Statistical consistency of sign-switching vacuum energy with cosmological observations
Using exact non-Gaussian shift and posterior predictive tests, ΛsCDM improves CMB–BAO consistency and softens but does not resolve the Hubble tension, which persists at p≈4×10⁻⁴.
-
How Holographic is the Dark Energy? A Spline Nodal reconstruction approach
A three-node spline reconstruction of holographic dark energy improves chi-squared over LambdaCDM by about 10 to 12, but Bayesian evidence gives no clear preference.
-
Cosmographic analysis of sign-switching dark energy
New sign-switching dark energy models with ladder, smooth-step and error-function profiles are introduced and compared, with continuous transitions shown to convert the Lambda_sCDM sudden singularity into a milder w-s...
-
Can the universe experience an AdS landscape since matter-radiation equality?
A universe with an AdS (negative cosmological constant) phase at recombination and another at low redshift is compatible with Planck, DESI, Pantheon Plus and SH0ES data, though not preferred by them.
-
Tsallis-Cirto Hubble parameter: Explaining DESI data and High redshift Supermassive Black Hole
The paper tunes a non-comoving-fluid Hubble parameter to the CMB angular scale, then uses the same curve to claim consistency with DESI/CC data and enough time for high-redshift black holes to grow.
-
An overview of what current data can (and cannot yet) say about evolving dark energy
The apparent preference for evolving dark energy depends strongly on which supernova catalog and which BAO survey are used, and is not robust across all independent data combinations.
-
Running Vacuum in the expanding Universe: a unified QFT paradigm for Inflation and Dark Energy
The running vacuum model derives dynamical vacuum energy from QFT in curved spacetime, using H^4 terms for inflation and H^2 terms for dark energy while G evolves logarithmically.
Discussion (0). Sign in to comment.