A Phantom Menace? Cosmological consequences of a dark energy component with super-negative equation of state
read the original abstract
It is extraordinary that a number of observations indicate that we live in a spatially flat, low matter density Universe, which is currently undergoing a period of accelerating expansion. The effort to explain this current state has focused attention on cosmological models in which the dominant component of the cosmic energy density has negative pressure, with an equation of state $w \ge -1$. Remarking that most observations are consistent with models right up to the $w=-1$ or cosmological constant ($\Lambda$) limit, it is natural to ask what lies on the other side, at $w<-1$. In this regard, we construct a toy model of a ``phantom'' energy component which possesses an equation of state $w<-1$. Such a component is found to be compatible with most classical tests of cosmology based on current data, including the recent type 1a SNe data as well as the cosmic microwave background anisotropy and mass power spectrum. If the future observations continue to allow $w<-1$, then barring unanticipated systematic effects, the dominant component of the cosmic energy density may be stranger than anything expected.
This paper has not been read by Pith yet.
Forward citations
Cited by 24 Pith papers
-
Cosmology of fractional gravity
Fractional gravity yields stable de Sitter expansion and exact bouncing solutions driven by phantom (w < -1) or ghost (negative energy) fluids, with results independent of the form-factor representation.
-
DESI DR2 Results II: Measurements of Baryon Acoustic Oscillations and Cosmological Constraints
DESI DR2 BAO data exhibits 2.3 sigma tension with CMB in Lambda-CDM but prefers evolving dark energy (w0 > -1, wa < 0) at 3.1 sigma with CMB and 2.8-4.2 sigma when including supernovae.
-
Evolving Dark Energy Is Vacuum Energy After All
A QCD-vacuum-based model of dynamical dark energy fits Planck+ACT+SPT, DESI DR2, and supernova data while reproducing the late-time evolution favored by DESI.
-
The Coherence Principle: A Falsifiable Prior for Model Selection from the Grammar of Theories
The Coherence Principle supplies a falsifiable prior for Bayesian model selection by converting compatibility with a theory's validated grammar into prior weights via a maximum-entropy exponential controlled by one parameter.
-
Affine ANEC selects the closed FRW branch for geodesically complete cosmology
Affine ANEC obstructs non-static flat and open FRW from being null geodesically complete while ANEC-satisfying, but allows explicit scalar-field realizations for closed FRW with NEC-respecting matter.
-
Open case for a closed universe
A no-go theorem proves flat and open FRW universes cannot be nonsingular, geodesically complete and ANEC-consistent while closed universes can, with positive curvature mimicking phantom dark energy at the 1% level.
-
Singularities in loop quantum cosmology
Loop quantum cosmology models harbor physical singularities or inconsistent space-time structures, with a new effective Friedmann equation revealing a sub-Planckian bounce after a singularity at infinite scale factor ...
-
New Rotating Black Hole in Electromagnetic Fields: Cosmological Horizon without Cosmological Constant
New exact Kerr black hole solution in an electromagnetic background spacetime that includes a cosmological horizon without a cosmological constant.
-
A Friendly Phantom: Late-time AdS-to-dS transition and cosmological tensions
Ph-Λ_sCDM realizes sign-switching dark energy via a phantom scalar on a tanh potential, enabling controlled AdS-to-dS transition without Big Rip.
-
Numerical Investigations of Stable Dynamics in the Presence of Ghosts
Numerical simulations reveal that ghost degrees of freedom in coupled scalar fields can support long-lived metastable dynamics when initial data are ultraviolet-dominated or small-amplitude and when certain potentials...
-
Numerical Investigations of Stable Dynamics in the Presence of Ghosts
Numerical simulations show ghost-normal scalar systems can remain dynamically bounded for long times when initial data is ultraviolet-dominated and low-amplitude, with some nonlinear potentials creating transient meta...
-
Reanalyzing DESI DR1: 2. Constraints on Dark Energy, Spatial Curvature, and Neutrino Masses
Reanalysis of DESI full-shape clustering data tightens constraints on neutrino mass, spatial curvature, and dark energy equation-of-state parameters relative to BAO-only results.
-
The general static spherical perfect fluid solution with EoS parameter w=-1/6
The general static spherical perfect fluid solution with EoS parameter w=-1/6 is obtained analytically via Buchdahl transformation of a known solution.
-
$\Lambda$CDM-like models with future singularities
Dark energy models with pressure defined as a function of scale factor match ΛCDM observations today but develop finite-time future singularities, including exact scalar field representations and calculated effects on...
-
Quintom Model Perturbations
A two-field quintom model reproduces w0waCDM perturbation features and is mildly favored over it in Bayesian fits to BAO, CMB, and SNIa data.
-
Late-Time Cosmology and Structure Formation in Quadratic $f(Q)$ Gravity
Quadratic f(Q) gravity adds an H^4 term to the Friedmann equation and introduces a time-dependent G_eff that suppresses linear growth and halo abundance, offering a modified-gravity route to easing the S8 tension.
-
Coupled Dark Energy and Dark Matter for DESI: An Effective Guide to the Phantom Divide
Coupled quintessence-dark matter models can produce an apparent phantom-crossing effective equation of state matching DESI preferences if the scalar field begins frozen in the radiation era.
-
Extended Dark Energy analysis using DESI DR2 BAO measurements
Extended analysis of DESI DR2 data confirms robust evidence for dynamical dark energy with phantom crossing preference, stable under parametric and non-parametric modeling.
-
Effective Phantom Dark Energy: What Cosmological Reconstruction Does and Does Not Imply
Effective phantom dark energy is a background-level reconstruction that does not imply fundamental pathologies such as ghost instabilities or null energy condition violation by the underlying stress tensor.
-
Early- and Late-Time Modifications to $\Lambda$CDM: Implications for the Hubble Tension
An extended model with decaying dark matter around equality and w0 dark energy yields H0 ≈ 70 km/s/Mpc from Planck+ACT+DESI data, reducing Hubble tension to ~2.2σ while producing Bayesian evidence comparable to ΛCDM.
-
The Quintom theory of dark energy after DESI DR2
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 i...
-
Finite scale factor and future singularities
Dark energy models with pressure as a function of scale factor produce type I-IV finite-time future singularities that exhibit similar late-time behavior.
-
The Hubble Tension and Early Dark Energy
The Hubble tension between local and early-universe expansion-rate measurements may be resolved by early dark energy that speeds up expansion before recombination while satisfying existing constraints.
-
Dark Energy in the DESI Era: A Brief Review of Evidence, Beyond-$\Lambda$CDM Interpretations, and Tensions
Review of DESI evidence for dynamical dark energy, its dependence on parametrization and datasets, and alternative beyond-LambdaCDM interpretations that may address cosmological tensions.
discussion (0)
Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.