Soft limits in holographic cosmology

McFadden, Paul

Abstract

We study the soft limits of cosmological correlators from a holographic perspective, showing how the inflationary consistency relations arise from the diffeomorphism invariance of the dual quantum field theory. Starting from the corresponding Ward identity, by taking moments we derive the leading and subleading behaviour of the stress tensor 3-point function in the limit as one momentum vanishes. These results are non-perturbative and valid in quantum field theories of a very general nature. Exploiting the known mapping of correlators in the dual quantum field theory to those of the cosmology, we then obtain the leading and subleading soft behaviour of all cosmological 3-point correlators of curvature perturbations and gravitons. Our results thus provide a holographic derivation of all leading and subleading consistency relations for cosmological 3-point functions, and our method is easily generalised. We verify our results explicitly for slow-roll inflation and for strongly coupled holographic cosmologies with a perturbative dual description.

Citation

McFadden, P. (2015). Soft limits in holographic cosmology. Journal of High Energy Physics, 2015(02), Article 053. https://doi.org/10.1007/jhep02%282015%29053

• Journal Article Type: Article
• Acceptance Date: Jan 12, 2015
• Online Publication Date: Feb 10, 2015
• Publication Date: Feb 10, 2015
• Deposit Date: Oct 26, 2017
• Publicly Available Date: May 8, 2018
• Journal: Journal of High Energy Physics
• Print ISSN: 1126-6708
• Electronic ISSN: 1029-8479
• Publisher: Scuola Internazionale Superiore di Studi Avanzati (SISSA)
• Peer Reviewed: Peer Reviewed
• Volume: 2015
• Issue: 02
• Article Number: 053
• DOI: https://doi.org/10.1007/jhep02%282015%29053
• Public URL: https://durham-repository.worktribe.com/output/1345735
• Related Public URLs: https://arxiv.org/abs/1412.1874