Testing models of vacuum energy interacting with cold dark matter

Abstract

We test the models of vacuum energy interacting with cold dark matter and try to probe the possible deviation from the ΛCDM model using current observations. We focus on two specific models, Q = 3βHρΛ and Q = 3βHρc. The data combinations come from the Planck 2013 data, the baryon acoustic oscillations measurements, the type-Ia supernovae data, the Hubble constant measurement, the redshift space distortions data and the galaxy weak lensing data. For the Q = 3βHρc model, we find that it can be tightly constrained by all the data combinations, while for the Q = 3βHρΛ model, there still exist significant degeneracies between parameters. The tightest constraints for the coupling constant are β = −0.026 +0.036 −0.053 (for Q = 3βHρΛ) and β = −0.00045 ± 0.00069 (for Q = 3βHρc) at the 1σ level. For all the fit results, we find that the null interaction β = 0 is always consistent with data. Our work completes the discussion on the interacting dark energy model in the recent Planck 2015 papers. Considering this work together with the Planck 2015 results, it is believed that there is no evidence for the models beyond the standard ΛCDM model from the point of view of possible interaction.Modern cosmology encounters a great puzzle in explaining the late-time cosmic acceleration, as a universe with barotropic or pressureless fluids, evolving according to the laws of general relativity, cannot fit the observational data [1, 2]. This puzzle is phenomenologically solved by introducing a new component with negative pressure, generally called dark energy. However, the fundamental nature of dark energy is still unknown. At present, a cosmological constant Λ with equation of state w = −1 is the simplest candidate of dark energy, which, however, is plagued with the so-called fine-tuning problem and coincidence problem [3,4]. These theoretical problems provide cosmologists with the motivation to consider some complex theories for explaining the cosmic acceleration, such as the dynamical dark energy models or the modified gravity (MG) theories. In particular, in order to solve the coincidence problem, cosmologists have widely investigated the interacting dark energy (IDE) scenario , where dark energy directly interacts with dark matter by exchanging energy and momentum.Regardless of the theoretical problems of Λ, the Λ cold dark matter (ΛCDM) model is still the most competitive cosmological model and is now even taken as a prototype of the standard model in cosmology, as it can excellently fit most of the current data with the least free parameters [63]. Nevertheless, other complex models mentioned above are also not excluded by the observations. Given this fact, we still need to continuously test the validity of the ΛCDM model. Undoubtedly, any deviation from it, if confirmed by observations, would be a major breakthrough in cosmology. In fact, some degree of tension between different observations has been reported for the ΛCDM model since the Planck 2013 results were published [64]. This tension has attracted much interest * Correspon...

New constraints on interacting dark energy from cosmic chronometers

“…This is the main result of the present investigation, and it is in agreement with the results of other observational works [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23], however it has been arisen through the novel use of the recently released cosmic chronometers data.…”

“…Hence, many different scenarios of interacting dark energy have been constructed (see [7,8] for reviews and references therein). Interestingly enough, recently it has been shown that the current data might favor the late-time interaction between CDM and the vacuum energy [9][10][11][12] or the dynamical dark energy sector [13][14][15][16][17][18][19][20][21][22][23].…”

Dark calling dark: interaction in the dark sector in presence of neutrino properties after Planck CMB final release

“…It has been found that the presence of an interaction in the dark sector could successfully reconcile the long lasting cosmic coincidence problem [3,4,5,6,7]. Following this, a number of investigations in the context of interacting DE -DM models were performed by many investigators [8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43] (also see two review articles in this direction [44,45]). An interesting outcome from the interaction is that, it could naturally explain the phantom dark energy equation-ofstate [46,47,48,49].…”

Reexploration of interacting holographic dark energy model: cases of interaction term excluding the Hubble parameter

“…where Q is the phenomenological interaction term [113][114][115][116][117][118][119][120][121][122], denoting the energy transfer rate between dark energy and dark matter. In this paper, we consider the following five cases in the IHDE model:…”