Constraining the cosmology of the phantom brane using distance measures

Abstract

The phantom brane has several important distinctive features: (i) Its equation of state is phantomlike, but there is no future 'big rip' singularity, (ii) the effective cosmological constant on the brane is dynamically screened, because of which the expansion rate is smaller than that in ΛCDM at high redshifts. In this paper, we constrain the Phantom braneworld using distance measures such as Type Ia supernovae (SNeIa), Baryon Acoustic Oscillations (BAO), and the compressed Cosmic Microwave Background (CMB) data. We find that the simplest braneworld models provide a good fit to the data. For instance, BAO +SNeIa data can be accommodated by the braneworld for a large region in parameter space 0 ≤ Ω ℓ < ∼ 0.3 at 1σ. The Hubble parameter can be as high as H0 < ∼ 78 km s −1 Mpc −1 , and the effective equation of state at present can show phantom-like behaviour with w0 < ∼ − 1.2 at 1σ. We note a correlation between H0 and w0, with higher values of H0 leading to a lower, and more phantom-like, value of w0. Inclusion of CMB data provides tighter constraints Ω ℓ < ∼ 0.1. (Here Ω ℓ encodes the ratio of the five and four dimensional Planck mass.) The Hubble parameter in this case is more tightly constrained to H0 < ∼ 71 km s −1 Mpc −1 , and the effective equation of state to w0 < ∼ − 1.1. Interestingly, we find that the universe is allowed be closed or open, with −0.5 < ∼ Ωκ < ∼ 0.5, even on including the compressed CMB data. There appears to be some tension in the low and high z BAO data which may either be resolved by future data, or act as a pointer to interesting new cosmology.

Hubble Parameter Measurement Constraints on the Redshift of the Deceleration–acceleration Transition, Dynamical Dark Energy, and Space Curvature

“…In Table 1 we collect 38 Hubble Delubac et al (2015), Moresco (2015), Alam et al (2016), and Moresco et al (2016). These data are plotted in the top panel of Figure 1.…”

Probing dark energy with braneworld cosmology in the light of recent cosmological data

“…no DE component, see 20,21 as interesting examples). However, a robust analysis of the DE dynamic in a simple brane scenario is needed.…”

“…Since we have not considered a selfconsistent brane perturbation theory, these compressed CMB information could lead to a (ΛCDM) biased brane tension constraint. 21,40 Nevertheless, as a first approach, we constrain the braneworld model parameters using the R, l A , and z * values for a flat w-CDM obtained from Planck measurements (R = 1.7492 ± 0.0049, l A = 301.787 ± 0.089, z * = 1089.99 ± 0.29 42 ). Planck also provide the following inverse covariance matrix, Cov …”

“…(20)(21)(22) were derived for the standard cosmology neglecting the possible brane effects. We assume as first approximation, that they are valid for our brane model.…”

Determining the Hubble Constant From Hubble Parameter Measurements

“…H(z) data have previously been used to constrain other cosmological parameters (see, e.g., Samushia & Ratra 2006;Chen & Ratra 2011b;Farooq et al , 2015Capozziello et al 2014;Chen et al 2015;Meng et al 2015;Alam et al 2016;Guo & Zhang 2016;Mukherjee 2016;Solà et al 2016), including measuring the redshift of the cosmological deceleration-acceleration transition between the earlier nonrelativistic matter-dominated epoch and the current dark-energy-dominated epoch (see, e.g., Moresco et al 2016). See Verde et al (2014) for an early attempt at measuring H 0 from H(z) data.…”