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Non-Gaussianity from Self-Ordering Scalar Fields

The Universe may harbor relics of the post-inflationary epoch in the form of a network of self-ordered scalar fields. Such fossils, while consistent with current cosmological data at trace levels, may leave too weak an imprint on the cosmic microwave background and the large-scale distribution of ma...

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Detalles Bibliográficos
Autores principales: Figueroa, Daniel G., Caldwell, Robert R., Kamionkowski, Marc
Lenguaje:eng
Publicado: 2010
Materias:
Acceso en línea:https://dx.doi.org/10.1103/PhysRevD.81.123504
http://cds.cern.ch/record/1246826
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author Figueroa, Daniel G.
Caldwell, Robert R.
Kamionkowski, Marc
author_facet Figueroa, Daniel G.
Caldwell, Robert R.
Kamionkowski, Marc
author_sort Figueroa, Daniel G.
collection CERN
description The Universe may harbor relics of the post-inflationary epoch in the form of a network of self-ordered scalar fields. Such fossils, while consistent with current cosmological data at trace levels, may leave too weak an imprint on the cosmic microwave background and the large-scale distribution of matter to allow for direct detection. The non-Gaussian statistics of the density perturbations induced by these fields, however, permit a direct means to probe for these relics. Here we calculate the bispectrum that arises in models of self-ordered scalar fields. We find a compact analytic expression for the bispectrum, evaluate it numerically, and provide a simple approximation that may be useful for data analysis. The bispectrum is largest for triangles that are aligned (have edges $k_1\simeq 2 k_2 \simeq 2 k_3$) as opposed to the local-model bispectrum, which peaks for squeezed triangles ($k_1\simeq k_2 \gg k_3$), and the equilateral bispectrum, which peaks at $k_1\simeq k_2 \simeq k_3$. We estimate that this non-Gaussianity should be detectable by the Planck satellite if the contribution from self-ordering scalar fields to primordial perturbations is near the current upper limit.
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spelling cern-12468262023-03-14T19:10:52Zdoi:10.1103/PhysRevD.81.123504http://cds.cern.ch/record/1246826engFigueroa, Daniel G.Caldwell, Robert R.Kamionkowski, MarcNon-Gaussianity from Self-Ordering Scalar FieldsAstrophysics and AstronomyThe Universe may harbor relics of the post-inflationary epoch in the form of a network of self-ordered scalar fields. Such fossils, while consistent with current cosmological data at trace levels, may leave too weak an imprint on the cosmic microwave background and the large-scale distribution of matter to allow for direct detection. The non-Gaussian statistics of the density perturbations induced by these fields, however, permit a direct means to probe for these relics. Here we calculate the bispectrum that arises in models of self-ordered scalar fields. We find a compact analytic expression for the bispectrum, evaluate it numerically, and provide a simple approximation that may be useful for data analysis. The bispectrum is largest for triangles that are aligned (have edges $k_1\simeq 2 k_2 \simeq 2 k_3$) as opposed to the local-model bispectrum, which peaks for squeezed triangles ($k_1\simeq k_2 \gg k_3$), and the equilateral bispectrum, which peaks at $k_1\simeq k_2 \simeq k_3$. We estimate that this non-Gaussianity should be detectable by the Planck satellite if the contribution from self-ordering scalar fields to primordial perturbations is near the current upper limit.The Universe may harbor relics of the post-inflationary epoch in the form of a network of self-ordered scalar fields. Such fossils, while consistent with current cosmological data at trace levels, may leave too weak an imprint on the cosmic microwave background and the large-scale distribution of matter to allow for direct detection. The non-Gaussian statistics of the density perturbations induced by these fields, however, permit a direct means to probe for these relics. Here we calculate the bispectrum that arises in models of self-ordered scalar fields. We find a compact analytic expression for the bispectrum, evaluate it numerically, and provide a simple approximation that may be useful for data analysis. The bispectrum is largest for triangles that are aligned (have edges $k_1\simeq 2 k_2 \simeq 2 k_3$) as opposed to the local-model bispectrum, which peaks for squeezed triangles ($k_1\simeq k_2 \gg k_3$), and the equilateral bispectrum, which peaks at $k_1\simeq k_2 \simeq k_3$. We estimate that this non-Gaussianity should be detectable by the Planck satellite if the contribution from self-ordering scalar fields to primordial perturbations is near the current upper limit.arXiv:1003.0672IFT-UAM-CSIC-10-09CERN-PH-TH-2010-039IFT-UAM-CSIC-10-09CERN-PH-TH-2010-039oai:cds.cern.ch:12468262010-03-04
spellingShingle Astrophysics and Astronomy
Figueroa, Daniel G.
Caldwell, Robert R.
Kamionkowski, Marc
Non-Gaussianity from Self-Ordering Scalar Fields
title Non-Gaussianity from Self-Ordering Scalar Fields
title_full Non-Gaussianity from Self-Ordering Scalar Fields
title_fullStr Non-Gaussianity from Self-Ordering Scalar Fields
title_full_unstemmed Non-Gaussianity from Self-Ordering Scalar Fields
title_short Non-Gaussianity from Self-Ordering Scalar Fields
title_sort non-gaussianity from self-ordering scalar fields
topic Astrophysics and Astronomy
url https://dx.doi.org/10.1103/PhysRevD.81.123504
http://cds.cern.ch/record/1246826
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