Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · 2610.23954

Probing generalized equation of state for dark energy with latest cosmological probes

Dadian Cheng·Shuo Cao·Yalong Nan·Xinyue Jiang·Sihan Li·Mingming Wang·Shijie Wang
View original source ↗Read source document ↗Export metadata ↓

Abstract

Baryon acoustic oscillation (BAO) measurements from DESI DR2 have strengthened indications of a time-evolving dark energy. In this paper, we investigate observational constraints on the generalized equation of state (GEoS) for dark energy, $w(a) = w_0 - w_β(a^β- 1)/β$, with latest data from UV and X-ray observations of high-redshift quasars, DESI DR2 BAO, Cosmic Microwave Background (CMB) data (including lensing) from Planck and the Atacama Cosmology Telescope (ACT), and Pantheon+ Type Ia Supernovae (SNe Ia). The full Quasar+BAO+CMB+SNe Ia data combination yields stringent constraints on the EoS parameters of $w_0=-0.840^{+0.057}_{-0.084}$, $w_β=-0.90^{+0.88}_{-0.23}$, and $β=2.2^{+2.4}_{-5.2}$. Specially, the $β$ parameter, which describe a broad range of dark energy evolution, is in perfect agreement with the Chevallier--Polarski--Linder model ($β=1$) -- the most widely used two-parameter parametrizations of dynamical dark energy. We also compare GEoS with other dynamical dark-energy parametrizations including CPL, Barboza--Alcaniz (BA) and Jassal--Bagla--Padmanabhan (JBP), and report three key findings. Firstly, we find compelling evidence for dynamical dark energy: all four EoS parametrizations yield lower information criterion (IC) values than $Λ$CDM for the full data combination, indicating a preference for EoS parametrizations under the Akaike information criterion (AIC) and the variance-based deviance information criterion (DIC). Secondly, although the unified phenomenological framework GEoS performs better than JBP, the current data do not strongly discriminate among different EoS parametrizations. Thirdly, the EoS trajectories of GEoS, CPL, and BA exhibit qualitatively similar transitions from the phantom regime at higher redshifts to the quintessence regime at late times, while the JBP parametrization exhibits a nonmonotonic evolution.

Explore related subjects

physics.gen-ph

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Dadian Cheng, Shuo Cao, Yalong Nan, Xinyue Jiang, Sihan Li, Mingming Wang, Shijie Wang. 2026-10-09. Probing generalized equation of state for dark energy with latest cosmological probes. https://arxiv.org/abs/2610.23954

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Fermions can also produce super-radiation phenomena

According to traditional theory, it is believed that Fermions do not exhibit superradiation. However, when predetermined boundary conditions are in place, there is a possibility of combining the wave function of coupled Fermions, which can result in the emergence of superradiation phenomena. This article presents a novel perspective, proposing that Fermions have the potential to display superradiation phenomena. This implies that there is a broader scope for investigating superradiation and its relationship with boundary conditions.

physics.gen-ph↗
arXiv2026

Finite-amplitude establishment beyond local invasion in cooperative chemical networks

Local kinetic exponents and next-generation radii diagnose infinitesimal invasion, but they need not determine whether a nonlinear organized state is accessible. Motivated by the kinetic component of Gate~7 in a twelve-gate nonequilibrium framework, we study cooperative networks whose productive linearization contains no closed cycle. We prove that an acyclic productive Jacobian has $R=0$ and $λ_{\rm kin}=-\min_i d_i<0$ for every drive, while a nonlinear return path can create a stable finite-amplitude branch through a saddle-node. In a canonical catalyst--assembly model, the saddle's stable manifold---not a threshold in either concentration---is the deterministic establishment boundary, so equal-abundance seeds of different composition can have opposite outcomes. At finite copy number, establishment becomes a committor and first-passage problem. For a benchmark protocol with $Γ=2$, $Ω=16$, $η=0.02$, and horizon $T=1000$, density-Hill and pair-count generators give first-entrance probabilities $0.633$ and $0.339$; their interpolated half-success drives are $1.900$ and $2.148$, an approximately $13.1\%$ shift. The associated constant-source deterministic system retains a stable low state, so these transitions are fluctuation- and discrete-arrival-enabled. The finite-amplitude regime is not confined to exact acyclicity: a weak linear return leaves a finite interval with $0<R<1$, $λ_{\rm kin}<0$, and bistability. A general cooperative-return criterion separates the superlinear local condition from the global return-profile structure required for a fold. The resulting hierarchy of branch existence, basin accessibility, and finite-time stochastic establishment replaces a single onset threshold by a protocol-dependent kinetic criterion.

physics.gen-ph↗
arXiv2026

All About the Galilean Group SGal(3)

We consider the Galilean group of affine transformations that preserve absolute time intervals between events in spacetime, as well as spatial distances between simultaneous events. The special Galilean group, SGal(3), is a 10-dimensional Lie group; we examine the structure of the group and its Lie algebra and discuss the representation of uncertainty on the group manifold. We also derive closed-form expressions for the $\LieGroupSGal{3}$ exponential and logarithmic maps, the Cayley and inverse Cayley maps, and the left Jacobian and its inverse. Along the way, we mention other groups, including the special orthogonal group, the special Euclidean group, and the group of extended poses, all of which are proper subgroups of the special Galilean group. We describe the role of time in Galilean relativity and touch on the relationship between temporal and spatial uncertainty.

physics.gen-ph↗