Cosmological perturbations in non-local higher-derivative gravity
Abstract
We study cosmological perturbations in a non-local higher-derivative model of gravity introduced by Biswas, Mazumdar and Siegel. We extend previous work, which had focused on classical scalar perturbations around a cosine hyperbolic bounce solution, in three ways. First, we point out the existence of a Starobinsky solution in this model, which is more attractive from a phenomenological point of view (even though it has no bounce). Second, we study classical vector and tensor pertuxsxrbations. Third, we show how to quantize scalar and tensor perturbations in a de Sitter phase (for choices of parameters such that the model is ghost-free). Our results show that the model is well-behaved at this level, and are very similar to corresponding results in local f(R) models. In particular, for the Starobinsky solution of non-local higher-derivative gravity, we find the same tensor-to-scalar ratio as for the conventional Starobinsky model.
- Publication:
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Journal of Cosmology and Astroparticle Physics
- Pub Date:
- November 2014
- DOI:
- 10.1088/1475-7516/2014/11/022
- arXiv:
- arXiv:1407.4982
- Bibcode:
- 2014JCAP...11..022C
- Keywords:
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- High Energy Physics - Theory;
- Astrophysics - Cosmology and Nongalactic Astrophysics;
- General Relativity and Quantum Cosmology
- E-Print:
- 28 pages