INFLATIONARY MODELS DRIVEN BY ADIABATIC MATTER CREATION

The flat inflationary dust universe with matter creation proposed by P rigogine and co-workers is generalized and its dynamical properties ar e reexamined. It is shown that the starting point of these models depe nds critically on a dimensionless parameter Sigma, closely related to the matter creation rate Psi. For Sigma bigger or smaller-than unity f lat universes can emerge, respectively, either like a big-bang FRW sin gularity or as a Minkowski spacetime at t = -infinity. The case Sigma = 1 corresponds to a de Sitter-type solution, a fixed point in the pha se diagram of the system, supported by the matter creation process. Th e curvature effects have also been investigated. The inflating de Sitt er is a universal attractor for all expanding solutions regardless of the initial conditions as well as of the curvature parameter.