### Abstract

Recently, Cormier and Holman pointed out that fluctuations of an inflaton field φ are significantly enhanced in the model of spinodal inflation with a potential V(φ) for which the second derivative V^{(2)}(φ) changes sign. As an application of this model, we investigate particle production in the natural inflation model with a potential V(φ)=m^{4}[1 + cos(φ/f)] by making use of the Hartree approximation. For typical mass scales f ∼m_{pl}∼10^{19} GeV and m∼m_{GUT}∼10^{16} GeV, we find that the growth of fluctuations relevantly occurs for the initial value of inflaton φ(0)≲0.1m_{pl}. Especially for φ(0)≲10^{-6}m_{pl}, maximum fluctuations are so large that secondary inflation takes place by produced fluctuations. In this case, the achieved number of e-foldings becomes much larger than in the case where an effect of spinodal instability is neglected.

Original language | English |
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Article number | 043505 |

Pages (from-to) | 1-9 |

Number of pages | 9 |

Journal | Physical Review D - Particles, Fields, Gravitation and Cosmology |

Volume | 62 |

Issue number | 4 |

Publication status | Published - 15 Aug 2000 |

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## Cite this

*Physical Review D - Particles, Fields, Gravitation and Cosmology*,

*62*(4), 1-9. [043505].