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Reconstructing the Cosmic Equation of State from Supernova distances

Tarun Deep Saini·Somak Raychaudhury·Varun Sahni·A. A. Starobinsky
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Abstract

Observations of high-redshift supernovae indicate that the universe is accelerating. Here we present a {\em model-independent} method for estimating the form of the potential $V(ϕ)$ of the scalar field driving this acceleration, and the associated equation of state $w_ϕ$. Our method is based on a versatile analytical form for the luminosity distance $D_L$, optimized to fit observed distances to distant supernovae and differentiated to yield $V(ϕ)$ and $w_ϕ$. Our results favor $w_ϕ\simeq -1$ at the present epoch, steadily increasing with redshift. A cosmological constant is consistent with our results.

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Tarun Deep Saini, Somak Raychaudhury, Varun Sahni, A. A. Starobinsky. 2000-10-07. Reconstructing the Cosmic Equation of State from Supernova distances. https://doi.org/10.1103/physrevlett.85.1162

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