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A non inflationary model with scale invariant cosmological perturbations

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arxiv hep-th/0610205 v1 pith:ZKFPWEUX submitted 2006-10-18 hep-th astro-phgr-qchep-ph

classification hep-thastro-phgr-qchep-ph
keywords perturbationsequationmathrmquantumalmostcosmologicaleffectsinvariant
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abstract

We show that a contracting universe which bounces due to quantum cosmological effects and connects to the hot big-bang expansion phase, can produce an almost scale invariant spectrum of perturbations provided the perturbations are produced during an almost matter dominated era in the contraction phase. This is achieved using Bohmian solutions of the canonical Wheeler-de Witt equation, thus treating both the background and the perturbations in a fully quantum manner. We find a very slightly blue spectrum ($n_{_\mathrm{S}}-1>0$). Taking into account the spectral index constraint as well as the CMB normalization measure yields an equation of state that should be less than $\omega\lesssim 8\times 10^{-4}$, implying $n_{_\mathrm{S}}-1 \sim \mathcal{O}(10^{-4})$, and that the characteristic size of the Universe at the bounce is $L_0 \sim 10^3 \ell_\mathrm{Planck}$, a region where one expects that the Wheeler-DeWitt equation should be valid without being spoiled by string or loop quantum gravity effects.

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Cited by 4 Pith papers

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

  1. Analytic Gravitational Wave Spectrum in Next-to-Minimal Bouncing Cosmology

    astro-ph.CO 2025-07 conditional novelty 6.0 of 10

    A five-phase bouncing cosmology yields a broken power-law gravitational wave spectrum whose amplitude bound automatically keeps the bounce energy below the Planck scale.

  2. Quasi-dust ekpyrotic scenario in Loop Quantum Cosmology

    gr-qc 2025-09 unverdicted novelty 5.0 of 10

    A quasi-dust ekpyrotic two-field model in Loop Quantum Cosmology produces viable primordial power spectra via coupled scalar and tensor perturbations.

  3. Black Hole Persistence in Scalar Tensor Theories

    gr-qc 2026-07 unverdicted novelty 4.0 of 10

    A perturbative scalar-tensor construction yields an evolving horizon of size proportional to the perturbation parameter that persists through a radiation-dominated bounce but evolves asymmetrically.

  4. Forecast Constraints on Bouncing Cosmology from High Frequency Gravitational Waves Using Superconducting LC Circuits and Resonant Cavities

    astro-ph.CO 2025-05 conditional novelty 4.0 of 10

    The paper forecasts that resonant-cavity and superconducting-circuit gravitational wave detectors could constrain the bounce energy scale of a generic bouncing cosmology far more tightly than astrophysical observatori...

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