Gauss–Bonnet Inflation and the String Swampland
The swampland criteria are generically in tension with single-field slow-roll inflation because the first swampland criterion requires small tensor-to-scalar ratio while the second swampland criterion requires either large tensor-to-scalar ratio or large scalar spectral tilt. The challenge to single...
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doaj-062e968e156a4c5b95c5716bbdd0c8b52020-11-25T01:08:44ZengMDPI AGUniverse2218-19972019-09-015920010.3390/universe5090200universe5090200Gauss–Bonnet Inflation and the String SwamplandZhu Yi0Yungui Gong1Department of Astronomy, Beijing Normal University, Beijing 100087, ChinaSchool of Physics, Huazhong University of Science and Technology, Wuhan 430074, Hubei, ChinaThe swampland criteria are generically in tension with single-field slow-roll inflation because the first swampland criterion requires small tensor-to-scalar ratio while the second swampland criterion requires either large tensor-to-scalar ratio or large scalar spectral tilt. The challenge to single-field slow-roll inflation imposed by the swampland criteria can be avoided by modifying the relationship between the tensor-to-scalar ratio and the slow-roll parameter. We show that the Gauss−Bonnet inflation with the coupling function inversely proportional to the potential overcomes the challenge by adding a constant factor in the relationship between the tensor-to-scalar ratio and the slow-roll parameter. For the Gauss−Bonnet inflation, while the swampland criteria are satisfied, the slow-roll conditions are also fulfilled, so the scalar spectral tilt and the tensor-to-scalar ratio are consistent with the observations. We use the potentials for chaotic inflation and the E-model as examples to show that the models pass all the constraints. The Gauss−Bonnet coupling seems a way out of the swampland issue for single-field inflationary models.https://www.mdpi.com/2218-1997/5/9/200inflationGauss–Bonnet inflationswampland |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Zhu Yi Yungui Gong |
spellingShingle |
Zhu Yi Yungui Gong Gauss–Bonnet Inflation and the String Swampland Universe inflation Gauss–Bonnet inflation swampland |
author_facet |
Zhu Yi Yungui Gong |
author_sort |
Zhu Yi |
title |
Gauss–Bonnet Inflation and the String Swampland |
title_short |
Gauss–Bonnet Inflation and the String Swampland |
title_full |
Gauss–Bonnet Inflation and the String Swampland |
title_fullStr |
Gauss–Bonnet Inflation and the String Swampland |
title_full_unstemmed |
Gauss–Bonnet Inflation and the String Swampland |
title_sort |
gauss–bonnet inflation and the string swampland |
publisher |
MDPI AG |
series |
Universe |
issn |
2218-1997 |
publishDate |
2019-09-01 |
description |
The swampland criteria are generically in tension with single-field slow-roll inflation because the first swampland criterion requires small tensor-to-scalar ratio while the second swampland criterion requires either large tensor-to-scalar ratio or large scalar spectral tilt. The challenge to single-field slow-roll inflation imposed by the swampland criteria can be avoided by modifying the relationship between the tensor-to-scalar ratio and the slow-roll parameter. We show that the Gauss−Bonnet inflation with the coupling function inversely proportional to the potential overcomes the challenge by adding a constant factor in the relationship between the tensor-to-scalar ratio and the slow-roll parameter. For the Gauss−Bonnet inflation, while the swampland criteria are satisfied, the slow-roll conditions are also fulfilled, so the scalar spectral tilt and the tensor-to-scalar ratio are consistent with the observations. We use the potentials for chaotic inflation and the E-model as examples to show that the models pass all the constraints. The Gauss−Bonnet coupling seems a way out of the swampland issue for single-field inflationary models. |
topic |
inflation Gauss–Bonnet inflation swampland |
url |
https://www.mdpi.com/2218-1997/5/9/200 |
work_keys_str_mv |
AT zhuyi gaussbonnetinflationandthestringswampland AT yunguigong gaussbonnetinflationandthestringswampland |
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