Cosmological Perturbations with Multiple Scalar Fields

J. Hwang; H. Noh

doi:10.1016/s0370-2693(00)01253-3

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arXiv · astro-ph/0009268

Cosmological Perturbations with Multiple Scalar Fields

J. Hwang·H. Noh

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Abstract

We consider the evolution of perturbed cosmological spacetime with multiple scalar fields in Einstein gravity. A complete set of scalar-type perturbation equations is presented in a gauge-ready form, and we derived the closed set of second-order differential equations in several useful forms. Conserved behaviors of the perturbed three-space curvature in the comoving gauge, $ϕ_v$, under several conditions are clarified. Under the slow-roll conditions, the adiabatic and isocurvature modes decouple from each other, and in the large-scale limit we have (i) the adiabatic mode is generally conserved, (ii) for a couple of special potential the isocurvature modes decouple from each other and are described by conserved quantities, (iii) in the two field system, the isocurvature mode is described by a conserved quantity for the general potential.

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J. Hwang, H. Noh. 2000-09-18. Cosmological Perturbations with Multiple Scalar Fields. https://doi.org/10.1016/s0370-2693(00)01253-3

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