Bispectrum from five-dimensional inflation
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arXiv
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| Main Authors: | , , , |
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| Format: | Preprint |
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2025
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| _version_ | 1866917145774915584 |
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| author | Antoniadis, Ignatios Chatrabhuti, Auttakit Cunat, Jules Isono, Hiroshi |
| author_facet | Antoniadis, Ignatios Chatrabhuti, Auttakit Cunat, Jules Isono, Hiroshi |
| contents | It was proposed that five-dimensional (5D) inflation can blow up the size of a compact dimension from the 5D Planck length to the micron size, as required by the dark dimension proposal, relating the weakness of the actual gravitational force to the size of the observable universe. Moreover, it was shown that 5D inflation can generate the (approximate) flat power spectrum of primordial density fluctuations consistent with present observations. Here we compute the bispectrum of primordial scalar perturbations and show that unlike the power spectrum, it differs from the four-dimensional case at all angular distances, due to the fact that in contrast to global dilatations, invariance under special conformal transformations is not restored at late times. Moreover there is an additional enhancement in the squeezed limit. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2505_14225 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Bispectrum from five-dimensional inflation Antoniadis, Ignatios Chatrabhuti, Auttakit Cunat, Jules Isono, Hiroshi High Energy Physics - Phenomenology Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology High Energy Physics - Theory It was proposed that five-dimensional (5D) inflation can blow up the size of a compact dimension from the 5D Planck length to the micron size, as required by the dark dimension proposal, relating the weakness of the actual gravitational force to the size of the observable universe. Moreover, it was shown that 5D inflation can generate the (approximate) flat power spectrum of primordial density fluctuations consistent with present observations. Here we compute the bispectrum of primordial scalar perturbations and show that unlike the power spectrum, it differs from the four-dimensional case at all angular distances, due to the fact that in contrast to global dilatations, invariance under special conformal transformations is not restored at late times. Moreover there is an additional enhancement in the squeezed limit. |
| title | Bispectrum from five-dimensional inflation |
| topic | High Energy Physics - Phenomenology Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology High Energy Physics - Theory |
| url | https://arxiv.org/abs/2505.14225 |