Cosmological correlators at the loop level
Abstract Cosmological correlators encode rich information about physics at the Hubble scale and may exhibit characteristic oscillatory signals due to the exchange of massive particles. Although many 1-loop processes, especially those that break de Sitter (dS) boosts, can generate significant leading...
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SpringerOpen
2025-03-01
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| Series: | Journal of High Energy Physics |
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| Online Access: | https://doi.org/10.1007/JHEP03(2025)051 |
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| author | Zhehan Qin |
| author_facet | Zhehan Qin |
| author_sort | Zhehan Qin |
| collection | DOAJ |
| description | Abstract Cosmological correlators encode rich information about physics at the Hubble scale and may exhibit characteristic oscillatory signals due to the exchange of massive particles. Although many 1-loop processes, especially those that break de Sitter (dS) boosts, can generate significant leading signals for various particle models in cosmological collider physics, the precise results for these correlators or their full signals remain unknown due to the lack of symmetry. In this work, we apply the method of partial Mellin-Barnes (PMB) representation to the calculation of cosmological correlators at the loop level. As a first step, we use the PMB representation to calculate four-point cosmological correlators with bubble topology. We find that both the nonlocal and local signals arise from the factorized part, validating the cutting rules proposed in previous work, and are free from ultraviolet (UV) divergence. Furthermore, the UV divergence originates solely from the background piece and can be manifestly canceled by introducing the appropriate counterterm, similar to the procedure in flat spacetime. We also demonstrate how to renormalize the 1-loop correlators in Mellin space. After a consistency check with known results for the covariant case, we provide new analytical results for the signals generated from a nontrivial dS-boost-breaking bubble. |
| format | Article |
| id | doaj-art-a8c4d24f03a84ee799dd8f3efedc27ba |
| institution | DOAJ |
| issn | 1029-8479 |
| language | English |
| publishDate | 2025-03-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Journal of High Energy Physics |
| spelling | doaj-art-a8c4d24f03a84ee799dd8f3efedc27ba2025-08-20T03:06:48ZengSpringerOpenJournal of High Energy Physics1029-84792025-03-012025314210.1007/JHEP03(2025)051Cosmological correlators at the loop levelZhehan Qin0Department of Physics, Tsinghua UniversityAbstract Cosmological correlators encode rich information about physics at the Hubble scale and may exhibit characteristic oscillatory signals due to the exchange of massive particles. Although many 1-loop processes, especially those that break de Sitter (dS) boosts, can generate significant leading signals for various particle models in cosmological collider physics, the precise results for these correlators or their full signals remain unknown due to the lack of symmetry. In this work, we apply the method of partial Mellin-Barnes (PMB) representation to the calculation of cosmological correlators at the loop level. As a first step, we use the PMB representation to calculate four-point cosmological correlators with bubble topology. We find that both the nonlocal and local signals arise from the factorized part, validating the cutting rules proposed in previous work, and are free from ultraviolet (UV) divergence. Furthermore, the UV divergence originates solely from the background piece and can be manifestly canceled by introducing the appropriate counterterm, similar to the procedure in flat spacetime. We also demonstrate how to renormalize the 1-loop correlators in Mellin space. After a consistency check with known results for the covariant case, we provide new analytical results for the signals generated from a nontrivial dS-boost-breaking bubble.https://doi.org/10.1007/JHEP03(2025)051de Sitter spaceScattering AmplitudesEarly Universe Particle PhysicsCosmology of Theories BSM |
| spellingShingle | Zhehan Qin Cosmological correlators at the loop level Journal of High Energy Physics de Sitter space Scattering Amplitudes Early Universe Particle Physics Cosmology of Theories BSM |
| title | Cosmological correlators at the loop level |
| title_full | Cosmological correlators at the loop level |
| title_fullStr | Cosmological correlators at the loop level |
| title_full_unstemmed | Cosmological correlators at the loop level |
| title_short | Cosmological correlators at the loop level |
| title_sort | cosmological correlators at the loop level |
| topic | de Sitter space Scattering Amplitudes Early Universe Particle Physics Cosmology of Theories BSM |
| url | https://doi.org/10.1007/JHEP03(2025)051 |
| work_keys_str_mv | AT zhehanqin cosmologicalcorrelatorsatthelooplevel |