Primordial non-Gaussianity from ultra slow-roll Galileon inflation
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arXiv
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| Autores principales: | , , , |
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| Formato: | Preprint |
| Publicado: |
2023
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| _version_ | 1866910292400668672 |
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| author | Choudhury, Sayantan Karde, Ahaskar Panda, Sudhakar Sami, M. |
| author_facet | Choudhury, Sayantan Karde, Ahaskar Panda, Sudhakar Sami, M. |
| contents | We present a detailed study of the generation of large primordial non-Gaussianities during the slow-roll (SR) to ultra-slow roll (USR) transitions in the framework of Galileon inflation. We found out that due to having sharp transitions in the USR phase, which persist with a duration of $Δ{\it N}_{\rm USR} \sim 2$ e-folds, we are able to generate the non-Gaussianity amplitude of the order: $|f_{\rm NL}| \sim {\it O}(10^{-2})$ in the SRI, $-5 < f_{\rm NL} < 5$ in the USR, and $-2 < f_{\rm NL} < 2$ in the SRII phases. As a result, we are able to achieve a cumulative average value of $|f_{\rm NL}| \sim {\it O}(1)$. This implies that our results strictly satisfy Maldacena's no-go theorem in the squeezed limit only for SRI, while they strictly violate the same condition in both the USR and SRII phases. The non-renormalization theorem in the Galileon theory helps to support our results regarding the generation of large mass primordial black holes along with large non-Gaussianities, which we show to be dependent on the specific positions of the transition wave numbers fixed at low scales. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2306_12334 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Primordial non-Gaussianity from ultra slow-roll Galileon inflation Choudhury, Sayantan Karde, Ahaskar Panda, Sudhakar Sami, M. Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology High Energy Physics - Phenomenology High Energy Physics - Theory We present a detailed study of the generation of large primordial non-Gaussianities during the slow-roll (SR) to ultra-slow roll (USR) transitions in the framework of Galileon inflation. We found out that due to having sharp transitions in the USR phase, which persist with a duration of $Δ{\it N}_{\rm USR} \sim 2$ e-folds, we are able to generate the non-Gaussianity amplitude of the order: $|f_{\rm NL}| \sim {\it O}(10^{-2})$ in the SRI, $-5 < f_{\rm NL} < 5$ in the USR, and $-2 < f_{\rm NL} < 2$ in the SRII phases. As a result, we are able to achieve a cumulative average value of $|f_{\rm NL}| \sim {\it O}(1)$. This implies that our results strictly satisfy Maldacena's no-go theorem in the squeezed limit only for SRI, while they strictly violate the same condition in both the USR and SRII phases. The non-renormalization theorem in the Galileon theory helps to support our results regarding the generation of large mass primordial black holes along with large non-Gaussianities, which we show to be dependent on the specific positions of the transition wave numbers fixed at low scales. |
| title | Primordial non-Gaussianity from ultra slow-roll Galileon inflation |
| topic | Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology High Energy Physics - Phenomenology High Energy Physics - Theory |
| url | https://arxiv.org/abs/2306.12334 |