Quintessential power-law cosmology: dark energy equation of state

Abstract

Power-law cosmology with scale factor as power of cosmic time, $a \propto t^{\a}$, is investigated. We review and discuss value of $\a$ obtained from various types of observation. Considering dark energy dominant era in late universe from $z<0.5$, we use observational derived results from Cosmic Microwave Background (WMAP7), Baryon Acoustic Oscillations (BAO) and observational Hubble data to find power exponent $\a$ and other cosmological variables. $\a$ is found to be $0.99\pm 0.02$ (WMAP7+BAO+$H_0$) and $0.99\pm 0.04$ (WMAP7). These values do not exclude possibility of acceleration at 1$\sigma$ hence giving viability to power-law cosmology in general. When considering scenario of canonical scalar field dark energy with power-law cosmology, we derive scalar field potential, exact scalar field solution and equation of state parameter. We found that the scenario of power-law cosmology containing dynamical canonical scalar field predicts present equation of state parameter $w_{\varphi ,0}=-0.449\pm 0.030$ while the $w$CDM with WMAP7 data (model independent, $w$ constant) allows a maximum (+1$\sigma$) value of $w_{\varphi ,0}$ at -0.70 which is off the prediction range. However, in case of varying $w_{\varphi }$, the $w_{\varphi ,0}$ value predicted from quintessential power-law cosmology is allowed within 1$\sigma$ uncertainty.

11 pages, 3 figures, Mod. Phys. Lett. A, to appear. arXiv admin note: substantial text overlap with arXiv:1201.3499

References in corpus (9)

• Dynamics of dark energy
• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Data Processing, Sky Maps, and Basic Results
• Spectra and Light Curves of Six Type Ia Supernovae at 0.511 < z < 1.12 and the Union2 Compilation
• Dynamics of a scalar field in Robertson-Walker spacetimes
• Testing power-law cosmology with galaxy clusters
• Interacting cosmic fluids in power-law Friedmann-Robertson-Walker cosmological models
• Direct Reconstruction of the Dark Energy Scalar-Field Potential
• Scalar field power-law cosmology with spatial curvature and dark energy-dark matter interaction

Cited by in corpus (4)

• Constraints on cosmological parameters in power-law cosmology
• Non-minimal derivative coupling gravity in cosmology
• Higgs potential from extended Brans-Dicke theory and the time-evolution of the fundamental constants
• Constraints on power law cosmology from cosmic chronometer, standard ruler, and standard candle data