Interacting Dark Energy Model Research Articles

IDECAMB: an implementation of interacting dark energy cosmology in CAMB

Interacting dark energy (IDE) scenario is a natural and important extension to the standard ΛCDM cosmology. We develop a full numerical routine, called IDECAMB, as a patch to the public Einstein-Boltzmann solver CAMB, to solve the background and perturbation equations of the IDE models. The IDECAMB solver provides a unified interface for the widely studied IDE models by employing a parametrization model with five free functions. By configuring these five functions, one can easily map the coupled quintessence (CQ) and coupled fluid (CF) models into the parametrization. We handle the perturbation evolutions of the CF models with the parametrized post-Friedmann (PPF) approach to avoid the possible large-scale instability. Compared with the previous established PPF approach whose form depends on a specific IDE model, the PPF approach in this work are model-independent, making it easy to use. We constrain a specific CQ model with the IDECAMB package. The fitting results are consistent with those obtained by Planck Collaboration, which confirms the validity of the package.

Constraining interacting dark energy models with the halo concentration–mass relation

ABSTRACT The interacting dark energy (IDE) model is a promising alternative cosmological model that has the potential to solve the fine-tuning and coincidence problems by considering the interaction between dark matter and dark energy. Previous studies have shown that the energy exchange between the dark sector components in this model can significantly affect the dark matter halo properties. In this study, by utilizing a large set of cosmological N-body simulations, we analyse the redshift evolution of the halo concentration–mass (c–M) relation in the IDE model, and show that the c–M relation is a sensitive proxy of the interaction strength parameter ξ2, especially at lower redshifts. Furthermore, we construct parametrized formulae to quantify the dependence of the c–M relation on ξ2 at redshifts ranging from z = 0 to z = 0.6. Our parametrized formulae provide a useful theoretical tool in constraining ξ2 with the observational c–M relation. As a first attempt, we use the data from X-ray, gravitational lensing, and galaxy rotational curve observations and obtain a tight constraint on ξ2, i.e. ξ2 = 0.071 ± 0.034. Our work demonstrates that the halo c–M relation, which reflects the halo assembly history, is a powerful probe to constrain the IDE model.

Exploring the H0 tension and the evidence for dark sector interactions from 2D BAO measurements

We explore observational constraints on a cosmological model with an interaction between dark energy (DE) and dark matter (DM), using a compilation of 15 measurements of the 2D baryon acoustic oscillation (BAO) (i.e., transversal) scale in combination with Planck-CMB data, to explore the parametric space of a class of interacting DE (IDE) models. We find that 2D BAO measurements can generate different observational constraints compared to the traditional approach of studying the matter clustering in the 3D BAO measurements. Contrary to the observations for the $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$ and IDE models when analyzed with $\mathrm{Planck}\text{\ensuremath{-}}\mathrm{CMB}+3\mathrm{D}$ BAO data, we note that $\mathrm{Planck}\text{\ensuremath{-}}\mathrm{CMB}+2\mathrm{D}$ BAO data favor high values of the Hubble constant ${H}_{0}$. From the joint analysis with $\mathrm{Planck}\text{\ensuremath{-}}\mathrm{CMB}+2\mathrm{D}$ $\mathrm{BAO}+\text{Gaussian}$ prior on ${H}_{0}$, we find ${H}_{0}=73.4\ifmmode\pm\else\textpm\fi{}0.88\text{ }\text{ }\mathrm{km}/\mathrm{s}/\mathrm{Mpc}$. We conclude that the ${H}_{0}$ tension is solved in the IDE model with strong statistical evidence (more than $3\ensuremath{\sigma}$) for the IDE cosmologies.

Reconstructing Torsion Cosmology from Interacting Holographic Dark Energy Model

We consider a cosmological model in the framework of Einstein–Cartan theory with a single scalar torsion ϕ=ϕ(t) and reconstruct the torsion model corresponding to the holographic dark energy (HDE) density. By studying the corresponding relation between the effective energy density of torsion field ρϕ and holographic dark energy density ρHDE, we naturally obtain a kind of torsion field from the interacting holographic dark energy with interaction term Q=−2ϕρm and ρm is the energy density of matter. We analyze the reconstructed torsion model and find that the torsion field behaves like the quintessence (w>−1) or quintom (exhibiting a transition from w>−1 to w<−1) dark energy, depending on the value of the model parameter c. We then perform a stability analysis according to the squared sound speed. It is shown that the model is classically stable in the current epoch for the case of c<1. We also investigate the model from the viewpoint of statefinder parameters and it turns out that the statefinder trajectories in the r−s plane behave differently for the three cases of c and also quite distinct from those of other cosmological models. From the trajectories of the statefinder pair {q,r}, we find that, for all the three cases of c, the universe has a phase transition from deceleration to acceleration, consistently with cosmological observations. In addition, we fit the reconstructed torsion model with the recent Type Ia supernovae (SNe Ia) samples, i.e., the Pantheon sample containing 1048 SNe Ia with the redshift in the range 0.01<z<2.3 and the Pantheon+ sample with 1701 light curves of 1550 distinct SNe Ia in the range 0.001<z<2.26. The analysis results show that the limits on the present fractional energy density of matter Ωm0 are completely compatible with those of the ΛCDM model obtained from the latest Planck mission observations at 68% confidence level. The mean value of c constrained from the Pantheon sample corresponds to the quintom-like scenario (i.e., c<1) and its mean value from the Pantheon+ sample corresponds to the quintessence-like scenario (i.e., c≥1). However, both of the Pantheon and Pantheon+ samples cannot distinguish the quintom-like and quintessence-like scenarios at 68% confidence level.

An An Interacting Dark Energy Model with Nonminimal Derivative Coupling in the Parameterized Post-Friedmannian Framework

We investigation the parameterization of the cosmological model with the nonminimal derivative coupling of a scalar field where gravity is coupled nonminimally with the derivatives of dark energy components in the form of a scalar field. We follow the parameterized post-Friedmannian approach for the interacting dark energy theories. We show how the big number of free functions can be reduced by limiting certain assumptions to a few non-zero coefficients. We only consider the case that the dark sector contains at most second order in time derivatives of the metric and scalar fields. In this paper, we demonstrate their use through an example of the dark sector interactions model and classify them according to the current literature.

Constraints on interacting dark energy models from time-delay cosmography with seven lensed quasars

ABSTRACT Measurements of time-delay cosmography of lensed quasars can provide an independent probe to explore the expansion history of the late-time Universe. In this paper, we employ the time-delay cosmography measurements from seven lenses (here abbreviated as the TD data) to constrain interacting dark energy (IDE) models. We mainly focus on the scenario of vacuum energy (with w = −1) interacting with cold dark matter, and consider four typical cases of the interaction form Q. When the TD data alone are employed, we find that the IDE models with Q ∝ ρde seem to have an advantage in relieving the H0 tension between the cosmic microwave background (CMB) and TD data. When the TD data are added to the CMB+BAO+SN+H0 data, we find that (i) the coupling parameter β in all the considered IDE models is positive within 1σ range, implying a mild preference for the case of cold dark matter decaying into dark energy; (ii) the IDE model with Q = βH0ρc slightly relieves the S8 tension, but the other considered IDE models further aggravate this tension; (iii) the Akaike information criteria of the IDE models with Q ∝ ρc are lower than that of the ΛCDM model, indicating that these IDE models are more preferred by the current mainstream data. We conclude that the considered IDE models have their own different advantages when the TD data are employed, and none of them can achieve good scores in all aspects.

Forecasts on interacting dark energy from the 21-cm angular power spectrum with BINGO and SKA observations

ABSTRACT Neutral hydrogen (H i) intensity mapping is a promising technique to probe the large-scale structure of the Universe, improving our understanding of the late-time accelerated expansion. In this work, we first scrutinize how an alternative cosmology, interacting dark energy (IDE), can affect the 21-cm angular power spectrum relative to the concordance ΛCDM model. We re-derive the 21-cm brightness temperature fluctuation in the context of such an interaction and uncover an extra new contribution. Then we estimate the noise level of three upcoming H i intensity mapping surveys, namely Baryon Acoustic Oscillations from Integrated Neutral Gas Observations (BINGO), Square Kilometre Array (SKA1)-MID Band 1 and Band 2, and employ a Fisher matrix approach to forecast their constraints on the IDE model. We find that while Planck 2018 maintains its dominion over early-Universe parameter constraints, BINGO and SKA1-MID Band 2 provide complementary bounding to the latest cosmic microwave background measurements on the dark energy equation of state w, the interacting strength λi and the reduced Hubble constant h, and that SKA1-MID Band 1 even outperforms Planck 2018 in these late-Universe parameter constraints. The expected minimum uncertainties are given by SKA1-MID Band 1 + Planck: $\sim 0.34{{\ \rm per\ cent}}$ on w, $\sim 0.22{{\ \rm per\ cent}}$ on h, $\sim 0.64{{\ \rm per\ cent}}$ on H i bias bHi, and an absolute uncertainty of about 3 × 10−4 (7 × 10−4) on λ1 (λ2). Moreover, we quantify the effects from systematics of the redshift bin number, redshift-space distortions, foreground residuals and uncertainties on the measured H i fraction, ΩHi(z). Our results indicate a bright prospect for H i intensity mapping surveys in constraining IDE, whether on their own or by synergies with other measurements.

Probing the effects of primordial black holes on 21-cm EDGES signal along with interacting dark energy and dark matter–baryon scattering

ABSTRACT21-cm radio signal has emerged as an important probe in investigating the dark age of the Universe (recombination to reionization). In the current analysis, we explore the combined effects of primordial black holes (PBHs), cooling-off of the baryonic matter due to dark matter (DM)–baryon collisions and interaction of DM and dark energy fluid on the 21-cm brightness temperature. The variation of brightness temperature shows remarkable dependence on DM mass (mχ) and the DM–baryon scattering cross-section (σ0). Bounds in mχ–σ0 parameter space are obtained for different possible PBH masses and for different interacting dark energy (IDE) models. These bounds are estimated based on the observed excess ($-500^{+200}_{-500}$ mK) of 21-cm brightness temperature by Experiment to Detect the Global Epoch of Reionization Signature experiment. Eventually, bounds on PBH mass is also obtained for different values of DM mass and for different IDE model coupling parameters. The compatibility of the constraints of the IDE models, in the estimated bounds is also addressed.

Prospects for Constraining Interacting Dark Energy Models with 21 cm Intensity Mapping Experiments

Abstract We forecast constraints on cosmological parameters in the interacting dark energy models using the mock data generated for neutral hydrogen intensity mapping (IM) experiments. In this work, we only consider the interacting dark energy models with energy transfer rate Q = β H ρ c and take BINGO, FAST, SKA1-MID, and Tianlai as typical examples of the 21 cm IM experiments. We find that the Tianlai cylinder array will play an important role in constraining the interacting dark energy model. Assuming perfect foreground removal and calibration and using the Tianlai-alone data, we obtain σ(H 0) = 0.19 km s−1 Mpc−1, σ(Ω m ) = 0.0033, and σ(σ 8) = 0.0033 in the IΛCDM model, which are much better than the results of Planck+optical BAO (i.e., optical galaxy surveys). However, the Tianlai-alone data cannot provide a very tight constraint on the coupling parameter β compared with Planck+optical BAO, while the Planck+Tianlai data can give a rather tight constraint of σ(β) = 0.00023 due to the parameter degeneracies being well broken by the data combination. In the IwCDM model, we obtain σ(β) = 0.00079 and σ(w) = 0.013 from Planck+Tianlai. In addition, we also make a detailed comparison among BINGO, FAST, SKA1-MID, and Tianlai in constraining the interacting dark energy models. We show that future 21 cm IM experiments will provide a useful tool for exploring the nature of dark energy and play a significant role in measuring the coupling between dark energy and dark matter.

Exploring the dark universe: Constraints on dynamical dark energy models from CMB, BAO and growth rate measurements

In order to explain the current acceleration of the universe, the fine-tuning problem of the cosmological constant [Formula: see text] and the cosmic coincidence problem, different alternative models have been proposed in the literature. We use the most recent observational data from CMB (Planck 2018 final data release) and LSS (SDSS, WiggleZ, VIPERS) to constrain dynamical dark energy (DE) models. The CMB shift parameter, which traditionally has been used to determine the main cosmological parameters of the standard model [Formula: see text], is employed in addition to data from redshift-space distortions through the growth parameter [Formula: see text] to constrain the mass variance [Formula: see text]. BAO data are also used to study the history of the cosmological expansion and the main properties of DE. From the evolution of [Formula: see text], we found a slowdown of acceleration behavior at low redshifts, and by using the Akaike and Bayesian Information Criteria (AIC, BIC), we discriminate different models to find those that are better suited to the observational data, finding that the interacting dark energy (IDE) model is the most favored by observational data, including information from SNIa and Hz. The analysis shows that the IDE model is followed closely by EDE and [Formula: see text] models, which in some cases fit better the observational data with individual probes.

Revisiting the Instability Problem of the Interacting Dark Energy Model in the Parameterized Post-Friedmann Framework

Abstract Dark energy might interact with dark matter in a direct, non-gravitational way, which can help remedy several theoretical defects. In order to find out the properties of interacting dark energy (IDE) models, it is necessary to investigate the cosmological perturbations in detail. However, due to the improper use of pressure perturbation of dark energy, a large-scale instability at the early stage occurs occasionally. In recent years, parameterized post-Friedmann approach has been used to calculate the perturbation equations in the IDE scenario. Under this framework, the dark energy pressure perturbation was replaced by the relationship between the momentum density of dark energy and other components on a large scale. However, this paper shows that if the interaction terms are related to the velocity perturbation of dark energy, the density perturbation of dark matter, and the matter power spectrum will diverge when the equation of state parameter of dark energy w is close to −1. A simple parameterization steering clear of this problem is proposed in this paper, which is a more general form and can be applied to explore the interaction between dark matter and dark energy by using various cosmological data.

Study of Interacting Dark Energy Model In (

We study the cosmological parameters (the equation of state parameter 𝜔ᴧthe decelaration parameter 𝑞, the geometrical statefinder parameters (𝑟 and 𝑠) and the slow roll parameters (𝜖 and 𝜂)), that used to describe the interacting holographic dark energy (IHDE) using Granda-Oliveros cutoff (𝐿𝐺𝑂) wit+ w+(𝑛+1) dimensional universe.

Testing the Interacting Dark Energy Model with Cosmic Microwave Background Anisotropy and Observational Hubble Data

The coupling between dark energy and dark matter provides a possible approach to mitigate the coincidence problem of the cosmological standard model. In this paper, we assumed the interacting term was related to the Hubble parameter, energy density of dark energy, and equation of state of dark energy. The interaction rate between dark energy and dark matter was a constant parameter, which was, Q = 3 H ξ ( 1 + w x ) ρ x . Based on the Markov chain Monte Carlo method, we made a global fitting on the interacting dark energy model from Planck 2015 cosmic microwave background anisotropy and observational Hubble data. We found that the observational data sets slightly favored a small interaction rate between dark energy and dark matter; however, there was not obvious evidence of interaction at the 1 σ level.

Instability of Interacting Ghost Dark Energy Model in an Anisotropic Universe

A new dark energy model called “ghost dark energy” was recently suggested to explain the observed accelerating expansion of the universe. This model originates from the Veneziano ghost of QCD. The dark energy density is proportional to Hubble parameter, ρΛ = αH, where α is a constant of order \({\Lambda }^{3}_{QCD}\) and ΛQCD ∼ 100MeV is QCD mass scale. In this paper, we investigate about the stability of generalized QCD ghost dark energy model against perturbations in the anisotropic background. At first, the ghost dark energy model of the universe with spatial BI model with/without the interaction between dark matter and dark energy is discussed. In particular, the equation of state and the deceleration parameters and a differential equation governing the evolution of this dark energy model are obtained. Then, we use the squared sound speed \({v_{s}^{2}}\) the sign of which determines the stability of the model. We explore the stability of this model in the presence/absence of interaction between dark energy and dark matter in both flat and non-isotropic geometry. In conclusion, we find evidence that the ghost dark energy might can not lead to a stable universe favored by observations at the present time in BI universe.

Exploring the full parameter space for an interacting dark energy model with recent observations including redshift-space distortions: Application of the parametrized post-Friedmann approach

Dark energy can modify the dynamics of dark matter if there exists a direct interaction between them. Thus a measurement of the structure growth, e.g., redshift-space distortions (RSD), can provide a powerful tool to constrain the interacting dark energy (IDE) models. For the widely studied $Q=3\beta H\rho_{de}$ model, previous works showed that only a very small coupling ($\beta\sim\mathcal{O}(10^{-3})$) can survive in current RSD data. However, all these analyses had to assume $w>-1$ and $\beta>0$ due to the existence of the large-scale instability in the IDE scenario. In our recent work [Phys. Rev. D 90, 063005 (2014)], we successfully solved this large-scale instability problem by establishing a parametrized post-Friedmann (PPF) framework for the IDE scenario. So we, for the first time, have the ability to explore the full parameter space of the IDE models. In this work, we reexamine the observational constraints on the $Q=3\beta H\rho_{de}$ model within the PPF framework. By using the Planck data, the baryon acoustic oscillation data, the JLA sample of supernovae, and the Hubble constant measurement, we get $\beta=-0.010^{+0.037}_{-0.033}$ ($1\sigma$). The fit result becomes $\beta=-0.0148^{+0.0100}_{-0.0089}$ ($1\sigma$) once we further incorporate the RSD data in the analysis. The error of $\beta$ is substantially reduced with the help of the RSD data. Compared with the previous results, our results show that a negative $\beta$ is favored by current observations, and a relatively larger interaction rate is permitted by current RSD data.

Statefinder and Om Diagnostics for Interacting New Holographic Dark Energy Model and Generalized Second Law of Thermodynamics

In this work, we have considered that the flat FRW universe is filled with the mixture of dark matter and the new holographic dark energy. If there is an interaction, we have investigated the natures of deceleration parameter, statefinder and Om diagnostics. We have examined the validity of the first and generalized second laws of thermodynamics under these interactions on the event as well as apparent horizon. It has been observed that the first law is violated on the event horizon. However, the generalized second law is valid throughout the evolution of the universe enveloped by the apparent horizon. When the event horizon is considered as the enveloping horizon, the generalized second law is found to break down excepting at late stage of the universe.

Cosmological Implications of Interacting Polytropic Gas Dark Energy Model in Non-flat Universe

The polytropic gas model is investigated as an interacting dark energy scenario. The cosmological implications of the model including the evolution of EoS parameter w Λ, energy density ΩΛ and deceleration parameter q are investigated. We show that, depending on the parameter of model, the interacting polytropic gas can behave as a quintessence or phantom dark energy. In this model, the phantom divide is crossed from below to up. The evolution of q in the context of polytropic gas dark energy model represents the decelerated phase at the early time and accelerated phase later. The singularity of this model is also discussed. Eventually, we establish the correspondence between interacting polytropic gas model with tachyon, K-essence and dilaton scalar fields. The potential and the dynamics of these scalar field models are reconstructed according to the evolution of interacting polytropic gas.

Evolution of Interacting Viscous Dark Energy Model in Einstein Cosmology

We investigate the evolution of the viscous dark energy (DE) interacting with the dark matter (DM) in the Einstein cosmology model. By using the linearizing theory of the dynamical system, we find that, in our model, there exists a stable late time scaling solution which corresponds to the accelerating universe. We also find the unstable solution under some appropriate parameters. In order to alleviate the coincidence problem, some authors considered the effect of quantum correction due to the conform anomaly and the interacting dark energy with the dark matter. However, if we take into account the bulk viscosity of the cosmic fluid, the coincidence problem will be softened just like the interacting dark energy cosmology model. That is to say, both the non-perfect fluid model and the interacting the dark energy cosmic model can alleviate or soften the singularity of the universe.

Comment on ``Interacting holographic dark energy model and generalized second law of thermodynamics in a non-flat universe", by M.R. Setare (JCAP 01 (2007) 023)

Author of ref. 1, M.R. Setare (JCAP 01 (2007) 023), by redefining the event horizon measured from the sphere ofthe horizon as the system's IR cut-off for an interactingholographic dark energy model in a non-flat universe, showed thatthe generalized second law of thermodynamics is satisfied for thespecial range of the deceleration parameter. His paper includes anerroneous calculation of the entropy of the cold dark matter. Alsothere are some missing terms and some misprints in the equations ofhis paper. Here we present that his conclusion is not true and thegeneralized second law is violated for the present timeindependently of the deceleration parameter.

Alleviation of cosmic age problem in interacting dark energy model

We investigate the cosmic age problem associated with the old high-z quasar APM 08279+5255 and the oldest globular cluster M 107, both being difficult to accommodate in ΛCDM model. By evaluating the age of the Universe in a model that has an extremely phantom like form of dark energy (DE), we show that simply introducing the dark energy alone does not remove the problem, and the interaction between dark matter (DM) and DE need to be taken into account. Next, as examples, we consider two interacting DE models. It is found that both these two interacting DE Models can predict a cosmic age much greater than that of ΛCDM model at any redshift, and thus substantially alleviate the cosmic age problem. Therefore, the interaction between DM and DE is the crucial factor required to make the predicted cosmic ages consistent with observations.