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Generating cosmological perturbations in non-singular Horndeski cosmologies

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arxiv 2207.04071 v3 pith:Q6KY5BSQ submitted 2022-07-08 hep-th gr-qc

Y. Ageeva , P. Petrov , V. Rubakov This is my paper · ORCID
classification hep-thgr-qc
keywords perturbationscosmologicalhorndeskimodelpastscalarsmallnessstrong
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abstract

We construct a concrete model of Horndeski bounce with strong gravity in the past. Within this model we show that the correct spectra of cosmological perturbations may be generated at early contracting epoch, with mild fine-tuning ensuring that the scalar spectral tilt $n_S$ and tensor-to-scalar ratio $r$ are consistent with observations. The smallness of $r$ is governed by the smallness of the scalar sound speed. Arbitrarily small values of $r$ are forbidden in our setup because of the strong coupling in the past. Nevertheless, we show that it is possible to generate perturbations in a controllable way, i.e. in the regime where the background evolution and perturbations are legitimately described within classical field theory and weakly coupled quantum theory.

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Cited by 3 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score. Full citation record

  1. Is there ghost and tachyon free bounce in UV complete gravity theory?

    gr-qc 2026-07 conditional novelty 6.0 of 10

    Ghost- and tachyon-free bounces in AID gravity require a negative cosmological constant; known positive-Λ solutions inevitably contain ghost radiation.

  2. Fully viable DHOST bounce with extra scalar

    hep-th 2025-01 conditional novelty 6.0 of 10

    A constructed two-field DHOST bouncing cosmology that avoids ghost, gradient, and superluminality problems and produces nearly scale-invariant curvature perturbations.

  3. Non-singular bounce solutions in Myrzakulov $f(R,T)$ gravity

    gr-qc 2025-01 reject novelty 4.0 of 10

    In Myrzakulov F(R,T) gravity, free connection functions can be chosen to produce matter-bounce backgrounds with a scale-invariant scalar power spectrum.

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