Perturbations in generalized multi-field inflation
By D. Langlois, S. Renaux-Petel. 2008
243 citations recorded by the source corpus.
We study the linear perturbations of multi-field inflationary models governed by a Lagrangian which is a general function of the scalar fields and of a global kinetic term combining their spacetime gradients with an arbitrary field space metric. Our analysis includes k-inflation, Dirac–Born–Infeld inflation and its multi-field extensions which have been recently studied. For this general class of models, we calculate the action to second order in the linear perturbations. We decompose the perturbations into an adiabatic mode, parallel to the background trajectory, and entropy modes. We show that all the entropy modes propagate with the speed of light whereas the adiabatic mode propagates with an effective speed of sound. We also identify the specific combination of entropy modes which sources the curvature perturbation on large scales. We then study in some detail the case of two scalar fields: we write explicitly the equations of motion for the adiabatic and entropy modes in a compact form and discuss their quantum fluctuations and primordial power spectra.
Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics
View Paper: https://www.semanticscholar.org/paper/74118cc7fb5164309ef940af379f16dfddd46578
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In Astronomy and Astrophysics
- Evangelos Sfakianakis
- Edward A. Mazenc
- Yi Wang
- David I. Kaiser
- Xingang Chen
- D. Baumann
- D. Green
- Masahide Yamaguchi
In Nuclear and High Energy Physics
Citations in the corpus
- Primordial bispectrum from multifield inflation with nonminimal couplings (2012, methodology): “In this paper we work in the Einstein frame, following the approach established in [6–9, 25, 30, 32–34].”
- Inflation, Cosmic Perturbations and Non-Gaussianities (2013, background): “This P (X,φ) class of models can also be generalized to multiple field case, where multi-field effects can appear even if the field space trajectory is a geodesic [148].”