First cosmological constraints on the superfluid Chaplygin gas model

Abstract

In this work we set observational constraints of the Superfluid Chaplygin gas model, which gives a unified description of the dark sector of the Universe as a Bose-Einstein condensate (BEC) that behaves as dark energy (DE) while it is in the ground state and as dark matter (DM) when it is in the excited state. We first show and perform the various steps leading to a form of the equations suitable for the observational tests to be carried out. Then, by using a Markov Chain Monte Carlo (MCMC) code, we constrain the model with a sample of cosmology-independent long gamma-ray bursts (LGRBs) calibrated using their Type I Fundamental Plane, as well as the Union2.1 set and observational Hubble parameter data. In this analysis, using our cosmological constraints, we sketch the effective equation of state parameter and deceleration parameter, and we also obtain the redshift of the transition from deceleration to acceleration: zt.PACS numbers: 98.80.Jk, 95.36.+x, 95.35.+d

Cosmological constraints on alternative model to Chaplygin fluid revisited

“…Several studies have constrained the (generalized) Chaplygin gas models in the cosmological context using SNIa, Hubble parameter measurements, gamma ray bursts, cosmic microwave background radiation and other probes, for instance see [28][29][30][31]. On the other hand, studies based on the matter power spectrum without baryons effects [32,33] rule out the GCG model.…”

Discriminating dark energy models by using the Statefinder hierarchy and the growth rate of matter perturbations

“…k 0 is associated to the ratio of normal and condensate density evaluated at present. The best-fit values of parameters we take are: k = 0.173 and k 0 = 0.297 [42]. (4) PKK is a class of k-essence with Lagrangian: p(X) = −V 0 √ 1 − 2X, where X ≡ 1 2 ∂ µ φ∂ µ φ is the the kinetic energy and V 0 is a constant potential [43,44].…”

Large-scale structure in superfluid Chaplygin gas cosmology

“…In Figs. 1 and 2, we plot numerically the linear growth factor D = D 1 (z)/D 1 (0) of the perturbations for different values of k 0 (with k = 0.173 obtained in [9]) and k (with k 0 = 0.287 obtained in [9]). The linear growth is normalized with the scale factor, a, the growth rate in the EdS universe (it is also equal to the growth rate in the ΛCDM universe at early times).…”

“…Recently, observational constraints on the generalized Chaplygin model have been considered in [7]. SCG has been analyzed from the point of view of statefinder [8] and has been constrained by using observational data [9].…”