CHAOS, FRACTALS, AND INFLATION

In order to draw out the essential behavior of the universe, investiga tions of early universe cosmology often reduce the complex system to a simple integrable system. Inflationary models are of this kind as the y focus on simple scalar field scenarios with correspondingly simple d ynamics. However, we can be assured that the universe is crowded with many interacting fields of which the inflaton is but one. As we descri be, the nonlinear nature of these interactions can result in a complex , chaotic evolution of the universe. Here we illustrate how chaotic ef fects can arise even in basic models such as homogeneous, isotropic un iverses with two scalar fields. We find inflating universes which act as attractors in the space of initial conditions. These universes disp lay chaotic transients in their early evolution. The chaotic character is reflected by the fractal border to the basin of attraction. The br oader implications are likely to be felt in the process of reheating a s well as in the nature of the cosmic background radiation.