Preheating with nonminimally coupled scalar fields in higher-curvature inflation models

In higher-curvature inflation models (R + alpha(n)R(n)), we study a parametric preheating of a scalar field chi coupled nonminimally to a spacetime curvature R(xi R chi(2)). In the case of the R-2-inflation model, efficient preheating becomes possible for rather small values of xi, i.e., \xi\less than or similar to several. Although the maximal fluctuation root[chi(2)](max)approximate to 2x10(17) GeV for xi approximate to -4 is almost the same as the chaotic inflation model with a nonminimally coupled chi held, the growth rate of the fluctuation becomes much larger and efficient preheating is realized. We also investigate preheating for the R-4 model and find that the maximal fluctuation is root[chi(2)](max) approximate to 8 x 10(16) GeV for xi approximate to -35. [S0556-2821(99)05522-8].