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| Main Authors: | , |
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| Format: | Preprint |
| Published: |
2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2504.18514 |
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| _version_ | 1866915259050098688 |
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| author | Kristiano, Jason Yokoyama, Jun'ichi |
| author_facet | Kristiano, Jason Yokoyama, Jun'ichi |
| contents | In cosmic inflation, non-linearities of the curvature perturbation can induce backreaction to the background. To obtain observational predictions at non-linear order on the correct background, one has to redefine the background or introduce background renormalization. We explicitly demonstrate it with a vanishing one-point function of the curvature perturbation as a renormalization condition, so that proper observational predictions can be made even at the nonlinear level. Due to non-linear symmetry of the curvature perturbation, such a procedure induces corrections to the two-point functions, which yield a finite renormalized one-loop correction that depends on the regularization scheme. Cancellation of the divergence is a manifestation of Maldacena's consistency condition. The finite term can be large and highly time-dependent, which indicates evolution outside the horizon. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2504_18514 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Inflationary background renormalization Kristiano, Jason Yokoyama, Jun'ichi High Energy Physics - Theory Cosmology and Nongalactic Astrophysics In cosmic inflation, non-linearities of the curvature perturbation can induce backreaction to the background. To obtain observational predictions at non-linear order on the correct background, one has to redefine the background or introduce background renormalization. We explicitly demonstrate it with a vanishing one-point function of the curvature perturbation as a renormalization condition, so that proper observational predictions can be made even at the nonlinear level. Due to non-linear symmetry of the curvature perturbation, such a procedure induces corrections to the two-point functions, which yield a finite renormalized one-loop correction that depends on the regularization scheme. Cancellation of the divergence is a manifestation of Maldacena's consistency condition. The finite term can be large and highly time-dependent, which indicates evolution outside the horizon. |
| title | Inflationary background renormalization |
| topic | High Energy Physics - Theory Cosmology and Nongalactic Astrophysics |
| url | https://arxiv.org/abs/2504.18514 |