Dark sector to restore cosmological concordance

In this article, we investigate the observational constraints for early universe as well as the late-time accelerated expansion of the universe in the realm of $f(\mathbb{T},\varphi)$ gravity, where $\mathbb{T}$ is the torsion scalar and $\varphi$ is a scalar field that modifying gravitational interactions. To analyze the early universe, we utilize the big bang nucleosynthesis (BBN) constraints while with cosmic chronometers (CC), baryon acoustic oscillation (BAO) and Markov Chain Monte Carlo (MCMC) analysis we dealt with the-late time accelerated expansion constraints. Focusing on three specific models within the framework of $f(\mathbb{T},\varphi)$ gravity, we assess whether the freeze-out temperature $T_f$ predicted by each model meets the latest BBN observational bounds $\bigg|\frac{\Delta T_f}{T_f}\bigg|$. To further evaluate the viability of these models in the late time universe, we analyze the Hubble parameter $H(z)$ across redshift $z$, utilizing CC and BAO datasets incorporating a $2-\sigma$ confidence region to ensure alignment with empirical data. Additionally, MCMC analysis using CC data provides detailed constraints on parameters and quantifies uncertainties through contour plots. Results indicate that each $f(T,\varphi)$ model satisfactorily aligns with observational data from BBN, CC, and BAO measurements, positioning this framework as a promising alternative to the standard $\Lambda$CDM cosmology. We wrap up by conducting a thorough analysis of how each model, dataset, and prior combination interacts, offering insights into their collective impact on the cosmological parameter estimations and the overall model evaluation.

The 21 cm intensity mapping (IM) technique provides us with an efficient way to observe the cosmic large-scale structure (LSS). From the LSS data, one can use the baryon acoustic oscillation and redshift space distortion to trace the expansion and growth history of the universe, and thus measure the dark energy parameters. In this paper, we make a forecast for cosmological parameter estimation with the synergy of three 21 cm IM experiments. Specifically, we adopt a novel joint survey strategy, FAST ($0<z<0.35$)+SKA1-MID ($0.35<z<0.8$)+HIRAX ($0.8<z<2.5$), to measure dark energy. We simulate the 21 cm IM observations under the assumption of excellent foreground removal. We find that the synergy of three experiments could place quite tight constraints on cosmological parameters. For example, it provides $\sigma(\Omega_{\rm m})=0.0039$ and $\sigma(H_0)=0.27\ \rm km\ s^{-1}\ Mpc^{-1}$ in the $\Lambda$CDM model. Notably, the synergy could break the cosmological parameter degeneracies when constraining the dynamical dark energy models. Concretely, the joint observation offers $\sigma(w)=0.019$ in the $w$CDM model, and $\sigma(w_0)=0.085$ and $\sigma(w_a)=0.32$ in the $w_0w_a$CDM model. These results are better than or equal to those given by CMB+BAO+SN. In addition, when the foreground removal efficiency is relatively low, the strategy still performs well. Therefore, the 21 cm IM joint survey strategy is promising and worth pursuing.

We study anisotropic (patchy) screening induced by the resonant conversion of cosmic microwave background (CMB) photons into dark-sector massive vector bosons (dark photons) as they cross non-linear large scale structure (LSS). Resonant conversion takes place through the kinetic mixing of the photon with the dark photon, one of the simplest low energy extensions to the Standard Model. In the early Universe, resonant conversion can occur when the photon plasma mass, obtained as the photon propagates through the ionized interstellar and intergalactic media, matches the dark photon mass. After the epoch of reionization, resonant conversion occurs mainly in the ionized gas that occupies virialized dark matter halos, for a range of dark photon masses between 10-13 eV ≲ m A' ≲ 10-11 eV. This leads to new CMB anisotropies that are correlated with LSS, which we refer to as patchy dark screening, in analogy with anisotropies from Thomson screening. Its unique frequency dependence allows it to be distinguished from the blackbody CMB. In this paper, we use a halo model approach to predict the imprint of dark screening on the CMB temperature and polarization anisotropies, as well as their correlation with LSS. We then examine the two- and three-point correlation functions of the dark-screened CMB, as well as correlation functions between CMB and LSS observables, to project the sensitivity of future measurements to the kinetic mixing parameter and dark photon mass. We demonstrate that an analysis with existing CMB data can improve upon current constraints on the kinetic mixing parameter by two orders of magnitude with the two-point correlation functions, while data from upcoming CMB experiments and LSS surveys can further improve the reach by another order of magnitude with two- and three-point correlation functions.

Relieve the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="d1e2446" altimg="si172.svg"><mml:msub><mml:mrow><mml:mi>H</mml:mi></mml:mrow><mml:mrow><mml:mn>0</mml:mn></mml:mrow></mml:msub></mml:math> tension with a new coupled generalized three-form dark energy model

We explore the role of redshift-space galaxy clustering data in constraining non-gravitational interactions between dark energy (DE) and dark matter (DM), for which state-of-the-art limits have so far been obtained from late-time background measurements. We use the joint likelihood for pre-reconstruction full-shape (FS) galaxy power spectrum and post-reconstruction Baryon Acoustic Oscillation (BAO) measurements from the BOSS DR12 sample, alongside Cosmic Microwave Background (CMB) data from \textit{Planck}: from this dataset combination we infer $H_0=68.02^{+0.49}_{-0.60}\,{\rm km}/{\rm s}/{\rm Mpc}$ and the 2$\sigma$ lower limit $\xi>-0.12$, among the strongest limits ever reported on the DM-DE coupling strength $\xi$ for the particular model considered. Contrary to what has been observed for the $\Lambda$CDM model and simple extensions thereof, we find that the CMB+FS combination returns tighter constraints compared to the CMB+BAO one, suggesting that there is valuable additional information contained in the broadband of the power spectrum. We test this finding by running additional CMB-free analyses and removing sound horizon information, and discuss the important role of the equality scale in setting constraints on DM-DE interactions. Our results reinforce the critical role played by redshift-space galaxy clustering measurements in the epoch of precision cosmology, particularly in relation to tests of non-minimal dark sector extensions of the $\Lambda$CDM model.

Using a joint statistical analysis, we test a four-dimensional FLRW model embedded in a five-dimensional bulk based on the Nash-Greene embedding theorem. Performing a Markov Chain Monte Carlo (MCMC) modelling, we combine observational data sets as those of the recent growth data, the best-fit Planck2018/varLambda CDM parameters on the Cosmic Microwave Background (CMB), the Baryon Acoustic Oscillations (BAO) measurements, the Pantheon Supernovae type Ia and the Hubble parameter data. From linear Nash-Greene fluctuations of the metric, we show the related perturbed equations in longitudinal Newtonian gauge to obtain the evolution of growth matter. A mild alleviation may be obtained from the degeneracies on the model parameter analyzing the sigma tension between the growth amplitude factor and the matter content in the plane (sigma _8-varOmega _m) on the observations from CMB and Large Scale Structure (LSS) probes. The Akaike Information Criterion (AIC) is also applied and we find a relative statistical consistence of the present model with both varLambda CDM and wCDM models lower than 1% of percentage difference at early times on the evolution of the Hubble function H(z). We also apply the Om(z) diagnosis to distinguish the present model from varLambda CDM and wCDM models.

Gravitational waves (GWs) passing through the Earth cause a correlated pattern of time-dependent deflections of the apparent position of astronomical sources.We build upon standard lensing reconstruction techniques to develop a new time-dependent optimal quadratic estimator, providing a novel technique to search for the deflections produced by GWs using observations of the cosmic microwave background (CMB).We find that the time-dependent deflection reconstruction is many orders of magnitude more sensitive than the ordinary static lensing estimator, and that it can be employed with the data collected by existing and future CMB surveys, without requiring any modification to the experimental or survey design.We demonstrate that CMB surveys offer sensitivity to GWs across a broad frequency range: while the sensitivity will not be competitive over the frequency range covered by pulsar timing arrays, the coverage band extend to both lower and higher frequencies.Finally, we discuss how our methods can be adapted to search for other time-varying signals, and also how they can be applied to surveys at other wavelengths.

The integrated Sachs–Wolfe effect in 4D Einstein–Gauss–Bonnet gravity

We demonstrate that pairwise peculiar velocity correlations for galaxy clusters can be directly reconstructed from the kinematic Sunyaev-Zel'dovich (kSZ) signature imprinted in the cosmic microwave background (CMB) using a machine learning model with a gradient boosting algorithm trained on high-fidelity kSZ simulations. The machine learning model is trained using six to seven cluster features that are directly related to observables from CMB and large-scale structure surveys. We validate the capabilities of the approach in light of the presence of primary CMB, detector noise, and potential uncertainties in the cluster mass estimate and cluster center location. The pairwise velocity statistics extracted using the techniques developed here have the potential to elicit valuable cosmological constraints on dark energy, modified gravity models, and massive neutrinos with kSZ measurements from upcoming CMB surveys, including the Simons Observatory, CMB-S4 and CCAT, and the DESI and SDSS galaxy surveys.

A promising idea to resolve the long standing Hubble tension is to postulate a new subdominant dark-energy-like component in the prerecombination Universe which is traditionally termed as the early dark energy (EDE). However, as shown in the Refs. [J. C. Hill et al., Early dark energy does not restore cosmological concordance, Phys. Rev. D 102, 043507 (2020), M. M. Ivanov et al.,Constraining early dark energy with large-scale structure, Phys. Rev. D 102, 103502 (2020).] the cosmic microwave background (CMB) and large-scale structure (LSS) data impose tight constraints on this proposal. Here, we revisit these strong bounds considering the Planck CMB temperature anisotropy data at large angular scales and the SPTPol polarization and lensing measurements. As advocated in [A. Chudaykin et al., Combined analysis of Planck and SPTPol data favors the early dark energy models, J. Cosmol. Astropart. Phys. 08 (2020) 013.] another paper, this combined data approach predicts the CMB lensing effect consistent with the $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$ expectation and allows one to efficiently probe both large and small angular scales. Combining Planck and SPTPol CMB data with the full-shape BOSS likelihood and information from photometric LSS surveys in the EDE analysis we found for the Hubble constant ${H}_{0}=69.79\ifmmode\pm\else\textpm\fi{}0.99\text{ }\text{ }\mathrm{km}\text{ }{\mathrm{s}}^{\ensuremath{-}1}\text{ }{\mathrm{Mpc}}^{\ensuremath{-}1}$ and for the EDE fraction ${f}_{\mathrm{EDE}}&lt;0.094(2\ensuremath{\sigma})$. These bounds obtained without including a local distance ladder measurement of ${H}_{0}$ (SH0ES) alleviate the Hubble tension to a $2.5\ensuremath{\sigma}$ level. Including further the SH0ES data we obtain ${H}_{0}=71.81\ifmmode\pm\else\textpm\fi{}1.19\text{ }\text{ }\mathrm{km}\text{ }{\mathrm{s}}^{\ensuremath{-}1}\text{ }{\mathrm{Mpc}}^{\ensuremath{-}1}$ and ${f}_{\mathrm{EDE}}=0.088\ifmmode\pm\else\textpm\fi{}0.034$ in full accordance with SH0ES. We also found that a higher value of ${H}_{0}$ does not significantly deteriorate the fit to the LSS data. Overall, the EDE scenario is (though weakly) favored over $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$ even after accounting for unconstrained directions in the cosmological parameter space. We conclude that the large-scale Planck temperature and SPTPol polarization measurements along with LSS data do not rule out the EDE model as a resolution of the Hubble tension. This paper underlines the importance of the CMB lensing effect for robust constraints on the EDE scenario.

We use the physically consistent tilted spatially flat and untilted non-flat ΛCDM inflation models to constrain cosmological parameter values with the Planck 2015 cosmic microwave background (CMB) anisotropy data and recent SNe Ia measurements, baryonic acoustic oscillations (BAO) data, growth rate observations, and Hubble parameter measurements. The most dramatic consequence of including the four non-CMB data sets is the significant strengthening of the evidence for non-flatness in the non-flat ΛCDM model, from 1.8σ for the CMB data alone to 5.1σ for the full data combination. The BAO data is the most powerful of the non-CMB data sets in more tightly constraining model-parameter values and in favoring a spatially closed universe in which spatial curvature contributes about a percent to the current cosmological energy budget. The untilted non-flat ΛCDM model better fits the large-angle CMB temperature anisotropy angular spectrum and is more consistent with the Dark Energy Survey constraints on the current value of the rms amplitude of mass fluctuations (σ 8) as a function of the current value of the nonrelativistic matter-density parameter (Ω m ) but does not provide as good a fit to the smaller-angle CMB temperature anisotropy data, as does the tilted flat-ΛCDM model. Some measured cosmological parameter values differ significantly between the two models, including the reionization optical depth and the baryonic matter density parameter, both of whose 2σ ranges (in the two models) are disjointed or almost so.

We explore and compare the capabilities of the recent observations of standard cosmological probes and the future observations of gravitational-wave (GW) standard sirens on constraining cosmological parameters. It is carried out in the frameworks of two typical dynamical models of cosmology, i.e., the $$\omega _0\omega _a$$ CDM model with $$\omega (z) = \omega _0 +\omega _a*z/(1+z)$$ , and the $$\xi $$ -index model with $$\rho _X\propto \rho _ma^{\xi }$$ , where $$\omega (z)$$ is the dark energy equation of state, and $$\rho _X$$ and $$\rho _m$$ are the energy densities of dark energy and matter, respectively. In the cosmological analysis, the employed data sets include the recent observations of the standard cosmological probes, i.e., Type Ia supernovae (SNe Ia), baryon acoustic oscillation (BAO) and cosmic microwave background (CMB), and also the mock GW standard siren sample with 1000 merging neutron star events anticipated from the third-generation detectors. In the scenarios of both $$\omega _0\omega _a$$ CDM and $$\xi $$ -index models, it turns out that the mock GW sample can reduce the uncertainty of the Hubble constant $$H_0$$ by about 50% relative to that from the joint SNe+BAO+CMB sample; nevertheless, the SNe+BAO+CMB sample demonstrates better performance on limiting other parameters. Furthermore, the Bayesian evidence is applied to compare the dynamical models with the $$\Lambda $$ CDM model. The Bayesian evidences computed from the SNe+BAO+CMB sample reveal that the $$\Lambda $$ CDM model is the most supported one; moreover, the $$\omega _0\omega _a$$ CDM model is more competitive than the $$\xi $$ -index model.

In this work, we perform reconstruction of \( f(Q) \) gravity inspired by the New Agegraphic Dark Energy (NADE) model, aiming to account for the Universe's late-time acceleration without invoking a cosmological constant. Utilizing a power law scale factor \( a(t) = a_0 t^h \), we derive an analytic form for \( f(Q) \) based on a correspondence with NADE, where the conformal time serves as the infrared cutoff. The resulting model naturally recovers General Relativity in the limit and exhibits a geometrically motivated dark energy component. We constrain the model parameters using recent Baryon Acoustic Oscillation (BAO) data from DESI DR2 BAO and previous BAO observations through the Markov Chain Monte Carlo (MCMC) analysis. The reconstructed Hubble parameter \( H(z) \) demonstrates excellent agreement with observational data, achieving high \( R^2 \) values and low \(\chi^2_{\min}\), AIC, and BIC scores, outperforming the standard \( \Lambda \)CDM model. Further, we investigate the cosmological evolution using the deceleration parameter \( q(z) \), effective equation of state \( \omega_{\mathrm{eff}}(z) \), and Om diagnostics. The model exhibits a clear transition from deceleration to acceleration with a present value \( q(0) \in \left[-0.5879, -0.3333\right] \) and transition redshift $z_{\mathrm{tr}} \sim 0.5209-0.8126$, while maintaining \( -1 &lt; \omega_{\mathrm{eff}}(z) &lt; -1/3 \), indicating quintessence like behavior. Om diagnostics consistently show a negative slope, further confirming deviation from \( \Lambda \)CDM. Energy condition analysis reveals that WEC, DEC, and NEC are satisfied, while SEC is violated only at low redshifts, which is consistent with cosmic acceleration. Also, stability analysis for the model shows stable behaviour under scalar perturbations. Overall, the reconstructed \( f(Q) \) model provides a viable, stable, observationally consistent, and theoretically motivated alternative to standard dark energy scenarios.

A Great Model Comparison Against the Cosmological Constant

Here, we present measurements of the Baryon Acoustic Oscillation (BAO) scale in redshift-space using the clustering of quasars. We consider a sample of 147,000 quasars from the extended Baryon Oscillation Spectroscopic Survey (eBOSS) distributed over 2044 square degrees with redshifts 0.8 &lt; z &lt; 2.2 and measure their spherically-averaged clustering in both configuration and Fourier space. Our observational dataset and the 1400 simulated realizations of the dataset allow us to detect a preference for BAO that is greater than 2.5σ . We determine the spherically averaged BAO distance to z = 1.52 to 4.4 per cent precision: D&lt;sub&gt;V&lt;/sub&gt; (z = 1:52) = 3855 170 (r&lt;sub&gt;d&lt;/sub&gt;/r&lt;sub&gt;d,fid&lt;/sub&gt;) Mpc. This is the first time the location of the BAO feature has been measured between redshifts 1 and 2. Our result is fully consistent with the prediction obtained by extrapolating the Planck flat CDM best-fit cosmology. All of our results are consistent with basic large-scale structure (LSS) theory, confirming quasars to be a reliable tracer of LSS, and provide a starting point for numerous cosmological tests to be performed with eBOSS quasar samples. We combine our result with previous, independent, BAO distance measurements to construct an updated BAO distance-ladder. Bu using these BAO data alone and marginalizing over the length of the standard ruler, we find Ω&lt;sub&gt;Λ&lt;/sub&gt; &gt; 0 at 6.5σ significance when testing a CDM model with free curvature.