Dias, Mafalda, Frazer, Jonathan, Mulryne, David J and Seery, David (2016) Numerical evaluation of the bispectrum in multiple field inflation. Journal of Cosmology and Astroparticle Physics, 2016 (12). 033. ISSN 1475-7516
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Abstract
We present a complete framework for numerical calculation of the power spectrum and bispectrum in canonical inflation with an arbitrary number of light or heavy fields. Our method includes all relevant effects at tree-level in the loop expansion, including (i) interference between growing and decaying modes near horizon exit; (ii) correlation and coupling between species near horizon exit and on superhorizon scales; (iii) contributions from mass terms; and (iv) all contributions from coupling to gravity. We track the evolution of each correlation function from the vacuum state through horizon exit and the superhorizon regime, with no need to match quantum and classical parts of the calculation; when integrated, our approach corresponds exactly with the tree-level Schwinger or 'in-in' formulation of quantum field theory. In this paper we give the equations necessary to evolve all two- and three-point correlation functions together with suitable initial conditions. The final formalism is suitable to compute the amplitude, shape, and scale dependence of the bispectrum in models with |fNL| of order unity or less, which are a target for future galaxy surveys such as Euclid, DESI and LSST. As an illustration we apply our framework to a number of examples, obtaining quantitatively accurate predictions for their bispectra for the first time. Two accompanying reports describe publicly-available software packages that implement the method.
Item Type: | Article |
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Schools and Departments: | School of Mathematical and Physical Sciences > Physics and Astronomy |
Research Centres and Groups: | Astronomy Centre |
Subjects: | Q Science > QB Astronomy > QB0980 Cosmogony. Cosmology |
Related URLs: | |
Depositing User: | David Seery |
Date Deposited: | 03 Jan 2017 11:04 |
Last Modified: | 20 Dec 2017 02:00 |
URI: | http://srodev.sussex.ac.uk/id/eprint/65990 |
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📧 Request an updateProject Name | Sussex Project Number | Funder | Funder Ref |
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Precisions tests of the inflationary scenario | G0918 | EUROPEAN UNION | 308082 |
Astronomy rolling grant | G0278 | STFC-SCIENCE AND TECHNOLOGY FACILITIES COUNCIL | ST/I000976/1 |
Philip Leverhulme Prize - David Seery | G0810 | LEVERHULME TRUST | PLP-2011-157 |