Is excess smoothing of Planck CMB ansiotropy data partially responsible for evidence for dark energy dynamics in other $w(z)$CDM parametrizations?
Chan-Gyung Park, Bharat Ratra
备注：
35 pages, 18 figures, 8 tables. Related to the analyses of arXiv:2405.00502 and arXiv:2410.13627. Accepted for publication in International Journal of Modern Physics D
We study spatially-flat dynamical dark energy parametrizations, $w(z)$CDM, with redshift-dependent dark energy equation of state parameter $w(z)$ expressed using three different quadratic and other polynomial forms (as functions of $1-a$, where $a$ is the scale factor), without and with a varying cosmic microwave background (CMB) lensing consistency parameter $A_L$. We use Planck CMB anisotropy data (P18 and lensing) and a large, mutually-consistent non-CMB data compilation that includes Pantheon+ type Ia supernova, baryon acoustic oscillation (BAO), Hubble parameter ($H(z)$), and growth factor ($fσ_8$) measurements, but not recent DESI BAO data. The six $w(z)$CDM ($+A_L$) parametrizations show higher consistency between the CMB and non-CMB data constraints compared to the XCDM ($+A_L$) and $w_0 w_a$CDM ($+A_L$) cases. Constraints from the most-restrictive P18+lensing+non-CMB data compilation on the six $w(z)$CDM ($+A_L$) parametrizations indicate that dark energy dynamics is favored over a cosmological constant by $\gtrsim 2σ$ when $A_L = 1$, but only by $\gtrsim 1σ$ when $A_L$ is allowed to vary (and $A_L>1$ at $\sim2σ$ significance). Non-CMB data dominate the P18+lensing+non-CMB compilation at low $z$ and favor quintessence-like dark energy. At high $z$ P18+lensing data dominate, favoring phantom-like dark energy with significance from $1.5σ$ to $2.9 σ$ when $A_L = 1$, and from $1.1σ$ to $1.8σ$ when $A_L$ varies. These results suggest that the observed excess weak lensing smoothing of some of the Planck CMB anistropy multipoles is partially responsible for the $A_L = 1$ cases $\gtrsim 2σ$ evidence for dark energy dynamics over a cosmological constant.
We place observational constraints on models with the late-time cosmic acceleration based on a number of parametrizations allowing fast transitions for the equation of state of dark energy. In addition to the model of Linder and Huterer where the dark energy equation of state $w$ monotonically grows or decreases in time, we propose two new parametrizations in which $w$ has an extremum. We carry out the likelihood analysis with the three parametrizations by using the observational data of supernovae type Ia, cosmic microwave background, and baryon acoustic oscillations. Although the transient c…
How Complex is Dark Energy? A Bayesian Analysis of CPL Extensions with Recent DESI BAO Measurements
Bu-Ali Sina University（布阿里·西纳大学）；Institute for Advanced Studies in Basic Sciences (IASBS)（基础科学高等研究所）；Institute for Research in Fundamental Sciences (IPM)（基础科学研究院）；Korea Institute for Advanced Study (KIAS)（韩国高等研究院）
We study the dynamical properties of dark energy based on a large family of PADE parameterizations for which the dark energy density evolves as a ratio between two polynomials in the scale factor of the universe. Using the latest cosmological data we perform a standard likelihood analysis in order to place constraints on the main cosmological parameters of different PADE models. We find that the basic cosmological parameters, namely $(Ω_{m0},h,σ_{8})$ are practically the same for all PADE parametrizations explored here. Concerning the free parameters which are related to dark energy we show th…
In the present work we perform a systematic analysis of a new dark energy parametrization and its various corrections at first and higher orders around the presence epoch $z=0$, where the first order correction of this dark energy parametrization recovers the known Chevallier-Polarski-Linder model. We have considered up to the third order corrections of this parametrization and investigate the models at the level of background and perturbations. The models have been constrained using the latest astronomical datasets from a series of potential astronomical data, such as the cosmic microwave bac…
$Λ$CDM and early dark energy in latent space: a data-driven parametrization of the CMB temperature power spectrum
Centre Universitaire d’Informatique, Université de Genève（日内瓦大学计算机中心）；William H. Miller III Department of Physics and Astronomy, Johns Hopkins University（约翰霍普金斯大学物理与天文学系）；Max-Planck-Institut für Astrophysik（马克斯·普朗克研究所（天体物理））；Universität Hamburg（汉堡大学）；Ludwig-Maximilians-Universität München（慕尼黑路德维希-马克西米利安大学）
In this paper, we have considered a spatially flat FRW universe filled with pressureless matter and dark energy. We have considered a phenomenological parametrization of the deceleration parameter $q(z)$ and from this we have reconstructed the equation of state for dark energy $ω_ϕ(z)$. This divergence free parametrization of the deceleration parameter is inspired from one of the most popular parametrization of the dark energy equation of state given by Barboza and Alcaniz. Using the combination of datasets (SN Ia $+$ Hubble $+$ BAO/CMB), we have constrained the transition redshift $z_{t}$ (at…
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We construct an updated and extended compilation of growth rate data consisting of 34 points and including corrections for model dependence. In order to maximize the independence of the datapoints we also construct a subsample of this compilation (`Gold' growth dataset) which consists of 18 datapoints. We test the consistency of this dataset with the best fit Planck15/$Λ$CDM parameters in the context of General Relativity (GR) using the evolution equation for the growth factor $δ(a)$ with a $w$CDM background. We find tension at the $\sim 3 σ$ level between the best fit parameters $w$ (the dark…
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Chevallier-Polarski-Linder (CPL) parametrization for the equation of state of dark energy in terms of cosmic redshift or scale factor have been frequently studied in the literature. In this study, we consider cosmic time based CPL parametrization for the equation of state parameter of the effective cosmic fluid that fills the fabric of spatially flat and homogeneous Robertson-Walker spacetime in general relativity. The model exhibits two worthy features: (i) It fits the observational data from the latest $H(z)$ and Union 2.1 SN Ia compilations matching the success of $Λ$CDM model. (ii) It desc…
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We re-examine the growth index of the concordance $Λ$ cosmology in the light of the latest 6dF and {\em WiggleZ} data. In particular, we investigate five different models for the growth index $γ$, by comparing their cosmological evolution using observational data of the growth rate of structure formation at different redshifts. Performing a joint likelihood analysis of the recent supernovae type Ia data, the Cosmic Microwave Background shift parameter, Baryonic Acoustic Oscillations and the growth rate data, we determine the free parameters of the $γ(z)$ parametrizations and we statistically q…
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The phenomenological parametrizations of dark-energy (DE) equation of state can be very helpful, since they allow for the investigation of its cosmological behavior despite the fact that its underlying theory is unknown. However, although there has been a large amount of research on DE parametrizations which involve two or more free parameters, the one-parameter parametrizations seem to be underestimated. We perform a detailed observational confrontation of five one-parameter DE models, with observational data from cosmic microwave background (CMB), Joint light-curve analysis sample from Super…
We discussed the dynamics of cosmological models in which the cosmological constant term is a time dependent function through the scale factor $a(t)$, Hubble function $H(t)$, Ricci scalar $R(t)$ and scalar field $ϕ(t)$. We considered five classes of models; two non-covariant parametrization of $Λ$: 1) $Λ(H)$CDM cosmologies where $H(t)$ is the Hubble parameter, 2) $Λ(a)$CDM cosmologies where $a(t)$ is the scale factor, and three covariant parametrization of $Λ$: 3) $Λ(R)$CDM cosmologies, where $R(t)$ is the Ricci scalar, 4) $Λ(ϕ)$-cosmologies with diffusion, 5) $Λ(X)$-cosmologies, where $X=\fra…
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In this paper, we study the evolution of dark matter perturbations in the linear regime by considering the possibility of dark energy perturbations. To do this, two popular parameterizations, CPL and BA with same number of free parameters and different redshift dependency have been considered. We integrate the full relativistic equations to obtain the growth of matter fluctuations for both clustering and smooth versions of CPL and BA dark energy. The growth rate is larger (smaller) than the $Λ$CDM in the smooth cases when $w<-1$ ($w>-1$) but the dark energy clustering gives a larger (smaller) …
Recent analyses in the literature suggest that the concordance $Λ$CDM model with rigid cosmological term, $Λ=$const., may not be the best description of the cosmic acceleration. The class of "running vacuum models", in which $Λ=Λ(H)$ evolves with the Hubble rate, has been shown to fit the string of $SNIa+BAO+H(z)+LSS+CMB$ data significantly better than the $Λ$CDM. Here we provide further evidence on the time-evolving nature of the dark energy (DE) by fitting the same cosmological data in terms of scalar fields. As a representative model we use the original Peebles & Ratra potential, $V\proptoΦ…
In the past decade or so observations of supernovae, Large Scale Structures (LSS), and the Cosmic Microwave Background (CMB) have confirmed the presence of what is called dark energy - the cause of accelerating expansion of the Universe. They have also measured its density as well as the value of other cosmological parameters according to the concordance $Λ$CDM model with few percent uncertainties. Next generation of surveys should allow to constrain this model with better precisions, or distinguish between a LCDM and alternative models such as modified gravity and (interacting)-quintessence m…
Most dark energy models have the $Λ$CDM as their limit, and if future observations constrain our universe to be close to $Λ$CDM Bayesian arguments about the evidence and the fine-tuning will have to be employed to discriminate between the models. Assuming a baseline $Λ$CDM model we investigate a number of quintessence and phantom dark energy models, and we study how they would perform when compared to observational data, such as the expansion rate, the angular distance, and the growth rate measurements, from the upcoming Dark Energy Spectroscopic Instrument (DESI) survey. We sample posterior l…
In the present investigation we use observational data of $ f σ_ {8} $ to determine observational constraints in the plane $(Ω_{m0},σ_{8})$ using two different methods: the growth factor parametrization and the numerical solutions method for density contrast, $δ_{m}$. We verified the correspondence between both methods for three models of accelerated expansion: the $ΛCDM$ model, the $ w_{0}w_{a} CDM$ model and the running cosmological constant $RCC$ model. In all case we consider also curvature as free parameter. The study of this correspondence is important because the growth factor parametri…
The $E_G$ statistic is a powerful probe for detecting deviations from GR by combining weak lensing (WL), real-space clustering and redshift space distortion (RSD) measurements thus probing both the lensing and the growth effective Newton constants ($G_L$ and $G_{eff}$). We construct an up to date compilation of $E_G$ statistic data including both redshift and scale dependence ($E_G(R,z)$). We combine this $E_G$ data compilation with an up to date compilation of $fσ_8$ data from RSD observations to identify the current level of tension between the Planck/$Λ$CDM standard model based on general r…
With the recent progresses on the Type II supernovae, we attempt to investigate whether there does exist new physics beyond the standard cosmological paradigm, i.e., the cosmological constant $Λ$ plus cold dark matter ($Λ$CDM). Constraining four alternative cosmological models with a data combination of currently available Type II supernovae calibrated by the standard color method, Type Ia supernovae, baryon acoustic oscillations, cosmic microwave background and cosmic chronometers, at the $1σ$ confidence level, we find that: (i) a spatially flat universe is supported for the non-flat $Λ$CDM m…
Model-independent late-universe measurements of $H_0$ and $Ω_K$ with the parametrization based on cosmic age-improved inverse distance ladder
College of Sciences, Northeastern University（东北大学理学院）；Institute of Theoretical Physics, Chinese Academy of Sciences（中国科学院理论物理研究所）；School of Physical Science and Technology, Ningbo University（宁波大学物理科学与技术学院）
Investigations on dark energy (DE) are currently inconclusive about its time evolution. Hints of this possibility do however glow now and then in the horizon. Herein we assess the current status of dynamical dark energy (DDE) in the light of a large body of updated $SNIa+H(z)+BAO+LSS+CMB$ observations, using the full Planck 2015 CMB likelihood. The performance of the $Λ$CDM model (with equation of state $w=-1$ for $Λ$) is confronted with that of the general XCDM and CPL parametrizations, as well as with the traditional $Φ$CDM model based on the scalar field potential $V\sim Φ^{-α}$. In particu…
No evidence for phantom crossing: local goodness-of-fit improvements do not persist under global Bayesian model comparison
University of the Western Cape（西开普大学）；National Institute for Theoretical & Computational Science（理论与计算科学国家研究所）；Missouri University of Science & Technology（密苏里科技大学）；University of Tokyo（东京大学）
$Om(z)$ is a diagnostic approach to distinguish dark energy models. However, there are few articles to discuss what is the distinguishing criterion. In this paper, firstly we smooth the latest observational $H(z)$ data using a model-independent method -- Gaussian processes, and then reconstruct the $Om(z)$ and its fist order derivative $\mathcal{L}^{(1)}_m$. Such reconstructions not only could be the distinguishing criteria, but also could be used to estimate the authenticity of models. We choose some popular models to study, such as $Λ$CDM, generalized Chaplygin gas (GCG) model, Chevallier-Po…
Dark Energy in the DESI Era: A Brief Review of Evidence, Beyond-$Λ$CDM Interpretations, and Tensions
College of Sciences, Northeastern University（东北大学理学院）；School of Fundamental Physics and Mathematical Sciences, Hangzhou Institute for Advanced Study, UCAS（杭州高等研究院基础物理与数学科学学院，UCAS）；School of Physical Sciences, University of Chinese Academy of Sciences（中国科学院大学物理科学学院）；MOE Key Laboratory of Data Analytics and Optimization for Smart Industry, Northeastern University（东北大学智能工业数据优化与分析教育部重点实验室）；National Frontiers Science Center for Industrial Intelligence and Systems Optimization, Northeastern University（东北大学工业智能与系统优化前沿科学中心）
Resolving the Planck-DESI tension by nonminimally coupled quintessence
Institute of Theoretical Physics, Chinese Academy of Sciences (CAS)（中国科学院理论物理研究所）；University of Chinese Academy of Sciences (UCAS)（中国科学院大学）；Institute of Fundamental Physics and Quantum Technology, Ningbo University（宁波大学基础物理与量子技术学院）；School of Fundamental Physics and Mathematical Sciences, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences（中国科学院大学杭州高等研究院基础物理与数学科学学院）；Asia Pacific Center for Theoretical Physics (APCTP)（亚太理论物理中心）
We consider cosmic chronometer (CC) data for the Hubble parameter, quasar (QSO) luminosities data of X-rays and ultraviolet rays emission, and the latest measurements of the present value of the Hubble parameter from 2018 Planck mission (PL18), and SH0ES observations (SHOES) to constrain the present value of cosmic curvature density parameter. We consider three kinds of dark energy models: the $Λ$CDM model, the wCDM model, and the CPL parametrization. In all these three models, we find higher values of the matter-energy density parameter, $Ω_{\rm m0}$ compared to the one obtained from the Plan…
In this paper, we propose a new parametrization of $Om(z)$ diagnostics and show how the most recent and significantly improved observations concerning the $H(z)$ and SN Ia measurements can be used to probe the consistency or tension between $Λ$CDM model and observations. Our results demonstrates that $H_0$ plays a very important role in the consistency test of $Λ$CDM with the $H(z)$ data. Adopting the Hubble constant priors from \textit{Planck} 2013 and Riess (2016), one finds a considerable tension between the current $H(z)$ data and $Λ$CDM model and confirms the conclusions obtained previous…
We study a generic class of time-evolving vacuum models which can provide a better phenomenological account of the overall cosmological observations as compared to the $Λ$CDM. Among these models, the running vacuum model (RVM) appears to be the most motivated and favored one, at a confidence level of $\sim 3σ$. We further support these results by computing the Akaike and Bayesian information criteria. Our analysis also shows that we can extract fair signals of dynamical dark energy (DDE) by confronting the same set of data to the generic XCDM and CPL parametrizations. In all cases we confirm t…
We study the cosmology with the running dark energy. The parametrization of dark energy with the respect to the redshift is derived from the first principles of quantum mechanics. Energy density of dark energy is obtained from the quantum process of transition from the false vacuum state to the true vacuum state. This is the class of the extended interacting $Λ$CDM models. We consider the energy density of dark energy parametrization $ρ_\text{de}(t)$, which follows from the Breit-Wigner energy distribution function which is used to model the quantum unstable systems. The idea that properties o…
We investigated the evolution of the background expansion and the growth rate of the matter density fluctuations in the scalar field $ϕ$CDM Ratra-Peebles model. We constrained the model parameter $α$ and the matter density parameter $Ω_{\rm m}$ using the recent measurements of the growth rate of the matter density fluctuations and baryon acoustic oscillation peak position. In addition, we studied a number of the $ϕ$CDM scalar field models in order to determine whether or not it would be possible to discriminate them from the $Λ$CDM model using predicted data for the future Dark Energy Spectros…
We investigate a second order $parabolic$ parametrization, $w(a)=w_t+w_a(a_t-a)^2$, which is a direct characterization of a possible $turning$ in $w$. The cosmological consequence of this parametrization is explored by using the observational data of the SNLS3 type Ia supernovae sample, the CMB measurements from WMAP9 and Planck, the Hubble parameter measurement from HST, and the baryon acoustic oscillation (BAO) measurements from 6dFGS, BOSS DR11 and improved WiggleZ. We found the existence of a turning point in $w$ at $a\sim0.7$ is favored at 1$σ$ CL. In the epoch $0.55< a< 0.9$, $w<-1$ is f…
