Ultra Slow-Roll Inflation and the non-Gaussianity Consistency Relation
By Jérôme Martin, H. Motohashi, T. Suyama. 2012
279 citations recorded by the source corpus.
Ultra slow-roll inflation has recently been used to challenge the non-Gaussianity consistency relation. We show that this inflationary scenario belongs to a one parameter class of models and we study its properties and observational predictions. We demonstrate that the power spectrum remains scale-invariant and that the bi-spectrum is of the local type with fnl=5(3-ns)/4 which, indeed, represents a modification of the consistency relation. However, we also show that the system is unstable and suffers from many physical problems among which is the difficulty to correctly WMAP normalize the model. We conclude that ultra slow-roll inflation remains a very peculiar case, the physical relevance of which is probably not sufficient to call into question the validity of the consistency relation.
Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics
View Paper: https://www.semanticscholar.org/paper/13f42eb58c31b37bd1d278b73d4cfb1435e40dcc
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Citations in the corpus
- On primordial black holes from an inflection point (2017, background): “In reality, close to an inflection point (and also close to a near inflection point used in [7]) the inflaton must either exit from inflation or enter an ultra-slow-roll regime [11, 12, 13, 14, 15, 16].”
- Steepest growth of the power spectrum and primordial black holes (2018, background): “If the potential is non-monotonic and the inflaton field rolls uphill then an arbitrarily negative value of η is possible, but the potential needs to be extremely tuned and will have many transients associated with it (which could end up dominating) [48].”
- Revisiting non-Gaussianity from non-attractor inflation models (2017, background): “Furthermore, it is important to notice that the non-attractor inflation alone is not phenomenologically viable [17, 18, 31].”
- Inflation with a constant rate of roll (2014, background): “Following [20], we adopt an ansatz of a constant rate of roll φ̈/Hφ̇ during inflation and parametrize it as φ̈ = −(3 + α)Hφ̇, (2.”
- Inflation, Cosmic Perturbations and Non-Gaussianities (2013, background): “However the non-Gaussianity becomes fNL ∼ 5/2, which is not only order one but also breaks the consistency relation of single field inflation [164, 165].”
- Primordial black holes from string inflation (2018, unknown): “These backgrounds are characterised by the parameter α defined as [72, 73]: φ̈ ≡ −(3 + α)Hφ̇ .”