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)=m4[1 + cos(φ/f)] by making use of the Hartree approximation. For typical mass scales f ∼mpl∼1019 GeV and m∼mGUT∼1016 GeV, we find that the growth of fluctuations relevantly occurs for the initial value of inflaton φ(0)≲0.1mpl. Especially for φ(0)≲10-6mpl, 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.
|Number of pages||9|
|Journal||Physical Review D - Particles, Fields, Gravitation and Cosmology|
|Publication status||Published - 15 Aug 2000|