Cargando…
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...
Autores principales: | , , |
---|---|
Lenguaje: | eng |
Publicado: |
2010
|
Materias: | |
Acceso en línea: | https://dx.doi.org/10.1103/PhysRevD.81.123504 http://cds.cern.ch/record/1246826 |
_version_ | 1780919513454215168 |
---|---|
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. |
id | cern-1246826 |
institution | Organización Europea para la Investigación Nuclear |
language | eng |
publishDate | 2010 |
record_format | invenio |
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 |
work_keys_str_mv | AT figueroadanielg nongaussianityfromselforderingscalarfields AT caldwellrobertr nongaussianityfromselforderingscalarfields AT kamionkowskimarc nongaussianityfromselforderingscalarfields |