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arXiv · 1110.4640

Horizon-preserving dualities and perturbations in non-canonical scalar field cosmologies

Ghazal Geshnizjani·William H. Kinney·Azadeh Moradinezhad Dizgah
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Abstract

We generalize the cosmological duality between inflation and cyclic contraction under the interchange $a \leftrightarrow H$ to the case of non-canonical scalar field theories with varying speed of sound. The single duality in the canonical case generalizes to a family of three dualities constructed to leave the cosmological acoustic horizon invariant. We find three classes of models: (I) DBI inflation, (II) the non-canonical generalization of cyclic contraction, and (III) a new cosmological solution with rapidly decreasing speed of sound and relatively slowly growing scale factor, which we dub {\it stalled} cosmology. We construct dual analogs to the inflationary slow roll approximation, and solve for the curvature perturbation in all three cases. Both cyclic contraction and stalled cosmology predict a strongly blue spectrum for the curvature perturbations inconsistent with observations.

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Ghazal Geshnizjani, William H. Kinney, Azadeh Moradinezhad Dizgah. 2011-11-08. Horizon-preserving dualities and perturbations in non-canonical scalar field cosmologies. https://doi.org/10.1088/1475-7516%2F2012%2F02%2F015

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