Classical approximation to quantum cosmological correlations
| dc.creator | van der Meulen, Meindert | |
| dc.creator | Smit, Jan | |
| dc.date | 2007-07-05 | |
| dc.date | 2008-02-21 | |
| dc.date.accessioned | 2026-07-07T11:41:25Z | |
| dc.date.available | 2026-07-07T11:41:25Z | |
| dc.description | We investigate up to which order quantum effects can be neglected in calculating cosmological correlation functions after horizon exit. As a toy model, we study $ϕ^3$ theory on a de Sitter background for a massless minimally coupled scalar field $ϕ$. We find that for tree level and one loop contributions in the quantum theory, a good classical approximation can be constructed, but for higher loop corrections this is in general not expected to be possible. The reason is that loop corrections get non-negligible contributions from loop momenta with magnitude up to the Hubble scale H, at which scale classical physics is not expected to be a good approximation to the quantum theory. An explicit calculation of the one loop correction to the two point function, supports the argument that contributions from loop momenta of scale $H$ are not negligible. Generalization of the arguments for the toy model to derivative interactions and the curvature perturbation leads to the conclusion that the leading orders of non-Gaussian effects generated after horizon exit, can be approximated quite well by classical methods. Furthermore we compare with a theorem by Weinberg. We find that growing loop corrections after horizon exit are not excluded, even in single field inflation. | |
| dc.description | 44 pages, 1 figure; v2: corrected errors, added references, conclusions unchanged; v3: added section in which we compare with stochastic approach; this version matches published version | |
| dc.identifier | https://arxiv.org/abs/0707.0842 | |
| dc.identifier | http://arxiv.org/abs/0707.0842 | |
| dc.identifier | JCAP0711:023,2007 | |
| dc.identifier | doi:10.1088/1475-7516/2007/11/023 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/200529 | |
| dc.subject | High Energy Physics - Theory | |
| dc.subject | Astrophysics | |
| dc.subject | General Relativity and Quantum Cosmology | |
| dc.subject | High Energy Physics - Phenomenology | |
| dc.title | Classical approximation to quantum cosmological correlations | |
| dc.type | text |