Journal Article

PUBDB-2026-00774

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Intrinsic non-Gaussianity of ultra slow-roll inflation

Ballesteros, G. ; Gambín Egea, J. ; Konstandin, T.DESY* ; Pérez Rodríguez, A. ; Pierre, M. (Corresponding author)DESY* ; Rey, J.DESY*

2026
IOP London

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Please use a persistent id in citations: doi:10.1088/1475-7516/2026/01/012  doi:10.3204/PUBDB-2026-00774

Report No.: DESY-24-205; IFT UAM-CSIC 24-183; arXiv:2412.14106

Abstract: We study the non-Gaussian tail of the curvature fluctuation, $\zeta$, in an inflationary scenario with a transient ultra slow-roll phase that generates a localized large enhancement of the spectrum of $\zeta$. To do so, we implement a numerical procedure that provides the probability distribution of $\zeta$ order by order in perturbation theory. The non-Gaussianities of $\zeta$ can be shown to arise from its non-linear relation to the inflaton fluctuations and from the intrinsic non-Gaussianities of the latter, which stem from its self interactions. We find that intrinsic non-Gaussianities, which have often been ignored to estimate the abundance of primordial black holes in this kind of scenario, are important. The relevance of the intrinsic contribution depends on the rapidity with which the transient ultra slow-roll phase occurs, as well as on its duration. Our method cannot be used accurately when the perturbative in-in formalism fails to apply, highlighting the relevance of developing fully non-perturbative approaches to the problem.

Keyword(s): inflation ; particle physics - cosmology connection ; primordial black holes

Note: 29 pages, 7 figures; added references and lightly extended discussion, results unaffected. Matches version to appear in JCAP

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Contributing Institute(s):

1. Theorie-Gruppe (T)

Research Program(s):

1. 611 - Fundamental Particles and Forces (POF4-611) (POF4-611)
2. DFG project G:(GEPRIS)390833306 - EXC 2121: Das Quantisierte Universum II (390833306) (390833306)
3. DFG project G:(GEPRIS)527296308 - Identifizierung des dunklen Sektors unseres Universums: Spuren früher Dynamik im späten Kosmos (527296308) (527296308)

Experiment(s):

1. No specific instrument

Appears in the scientific report 2026

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Database coverage:
; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Essential Science Indicators ; IF >= 5 ; JCR ; National-Konsortium ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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Linked articles:

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Preprint Konstandin, T.DESY* ; Ballesteros, G. ; Egea, J. G. ; Rodríguez, A. P. ; Pierre, M. (Corresponding author)DESY* ; Rey Idler, J. L.DESY*
Intrinsic non-Gaussianity of ultra slow-roll inflation
[10.3204/PUBDB-2024-07866]     Files  Fulltext by arXiv.org BibTeX | EndNote: XML, Text | RIS

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