Preheating in quintessential inflation

We perform a numerical study of the preheating mechanism of particle production in models of quintessential inflation and compare it with the usual gravitational production mechanism. We find that even for a very small coupling between the inflaton field and a massless scalar field, g greater than or similar to 10(-6), preheating dominates over gravitational particle production. Reheating temperatures in the range 10(4) less than or similar to T-rh less than or similar to 10(15) GeV can be easily obtained. (C) 2003 Published by Elsevier B.V.