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Covariant cosmological perturbation dynamics in the inflationary universe

Winfried Zimdahl
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Abstract

The linear cosmological perturbation theory of almost homogeneous and isotropic perfect fluid and scalar field universes is reconsidered and formally simplified. Using the existence of a covariant conserved quantity on large perturbation scales, a closed integral expression for comoving energy density perturbations is obtained for arbitrary equations of state. On this basis we establish a simple relation between fluid energy density perturbations at `reentry' into the horizon and the corresponding scalar field quantities at the first Hubble scale crossing during an early de Sitter phase of a standard inflationary scenario.

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Winfried Zimdahl. 1998-06-09. Covariant cosmological perturbation dynamics in the inflationary universe. https://arxiv.org/abs/gr-qc/9806045

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