An Exact Solution with Exit in the New Inflationary Universe Model

Taking the cosmological expansion rate directly as a function of the inflaton field instead of as a function of time, we present a new exact solution to Einstein's equations that describe the evolution of inflationary universe model. This includes a solution which has nearly exponential inflation for , and then develops smoothly towards radiation-like evolution for . The inflation is driven by the evolution of scalar field with inflation potential, V( ) = V₀ - m²/2 + λ/4. The spectral index of the scalar density, n_s, is computed and n_s lies well inside the limits set by the cosmic background explorer satellite.