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Gradient expansion(s) and dark energy

Massimo Giovannini
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Abstract

Motivated by recent claims stating that the acceleration of the present Universe is due to fluctuations with wavelength larger than the Hubble radius, we present a general analysis of various perturbative solutions of fully inhomogeneous Einstein equations supplemented by a perfect fluid. The equivalence of formally different gradient expansions is demonstrated. If the barotropic index vanishes, the deceleration parameter is always positive semi-definite.

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Massimo Giovannini. 2005-09-07. Gradient expansion(s) and dark energy. https://doi.org/10.1088/1475-7516%2F2005%2F09%2F009

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