Exploring the expanding Universe and dark energy using the statefinder diagnostic

By Ujjaini Alam, V. Sahni, T. D. Saini, A. Starobinsky. 2003

794 citations recorded by the source corpus.

The coming few years are likely to witness a dramatic increase in high-quality supernova data as current surveys add more high-redshift supernovae to their inventory and as newer and deeper supernova experiments become operational. Given the current variety in dark energy models and the expected improvement in observational data, an accurate and versatile diagnostic of dark energy is the need of the hour. This paper examines the statefinder diagnostic in the light of the proposed SuperNova Acceleration Probe (SNAP) satellite, which is expected to observe about 2000 supernovae per year. We show that the statefinder is versatile enough to differentiate between dark energy models as varied as the cosmological constant on one hand, and quintessence, the Chaplygin gas and braneworld models, on the other. Using SNAP data, the statefinder can distinguish a cosmological constant (w = -1) from quintessence models with w ≥ -0.9 and Chaplygin gas models with κ ≤ 15 at the 3a level if the value of Ω m is known exactly. The statefinder gives reasonable results even when the value of Ω m is known to only ∼20 per cent accuracy. In this case, marginalizing over Ω m and assuming a fiducial A-cold dark matter (LCDM) model allows us to rule out quintessence with w ≥ -0.85 and the Chaplygin gas with κ ≤ 7 (both at 3σ). These constraints can be made even tighter if we use the statefinders in conjunction with the deceleration parameter. The statefinder is very sensitive to the total pressure exerted by all forms of matter and radiation in the Universe. It can therefore differentiate between dark energy models at moderately high redshifts of z ≤ 10.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/f5874dcd82a901d798323824955a4f0209e4440b

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In Astronomy and Astrophysics

1. A. Starobinsky
2. Xin Zhang
3. Yi Wang
4. Shuang Wang
5. V. Sahni
6. Miao Li
7. A. Shafieloo
8. Ujjaini Alam

Citations in the corpus

• MODEL-INDEPENDENT EVIDENCE FOR DARK ENERGY EVOLUTION FROM BARYON ACOUSTIC OSCILLATIONS (2014, background): “One such diagnostic is the Statefinder r = ...a /aH 3 (also called the jerk) whose value remains at unity only in ΛCDM (Sahni et al. 2003; Alam et al. 2003) (also see Chiba & Nakamura 1998; Visser 2004).”
• A kinematical approach to dark energy studies (2006, background): “We note that Sahni et al. (2003) and Alam et al. (2003) also drew attention to the importance of the jerk parameter for discriminating models of dark energy and/or modified gravity.”
• Einstein's General Theory Of Relativity (2007, methodology): “Using the SNAP-specifications Alam and coworkers [ASSS03] have generated 1000 data sets for dl and z with accompanying uncertainties.”
• Smoothing supernova data to reconstruct the expansion history of the universe (2005, methodology): “Such models with constant equation of state are known as quiessence models of dark energy (Alam et al. 2003) and we shall refer to this model as the “quiessence model” throughout the paper.”
• Statefinder diagnosis for the interacting model of holographic dark energy (2007, methodology): “Since different cosmological models involving dark energy exhibit different evolution trajectories in the s− r plane, the statefinder can be used to diagnose different dark energy models [28].”