Deflation and matter creation

A nonsingular deflationary cosmology driven by adiabatic matter creation is proposed. The model evolves continuously from an initial de Sitter spaceti me towards a slightly modified Friedman-Robertson-Walker universe. The hori zon and flatness problems of the standard model are solved, but there is no supercooling and subsequent reheating as in standard inflation since entro py generation is concomitant with the deflationary process. Due to persiste nt adiabatic matter creation, the universe can be substantially older than 10 Gyr as predicted by the flat FRW model. (C) 1999 Published by Elsevier S cience B.V. All rights reserved.