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Anthropic Reasons for Non-Zero Flatness and Lambda

J. D. Barrow·H. B. Sandvik·J. Magueijo
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Abstract

In some cosmological theories with varying constants there are anthropic reasons why the expansion of the universe must not be too {\it close} to flatness or the cosmological constant too close to zero. Using exact theories which incorporate time-variations in $α$ and in $G$ we show how the presence of negative spatial curvature and a positive cosmological constant play an essential role in bringing to an end variations in the scalar fields driving time change in these 'constants' during any dust-dominated era of a universe's expansion. In spatially flat universes with $Λ=0$ the fine structure constant grows to a value which makes the existence of atoms impossible.

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J. D. Barrow, H. B. Sandvik, J. Magueijo. 2002-04-05. Anthropic Reasons for Non-Zero Flatness and Lambda. https://doi.org/10.1103/physrevd.65.123501

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