From instantons to inflationary universe
Khalatnikov I. M. , Schiller P.
The present paper is based on a theory which includes gravity and a complex scalar field.1 In such a theory it is possible to analyze the evolution from instantons in the classically forbidden (Euclidean) region in minisuperspace to the inflationary universe in the classically allowed (Minkowski) region. The characteristics for the Hamilton-Jacobi equation, which define the action in the quasiclassical approximation, are described by four first-order differential equations. This four-dimensional dynamical system was integrated numerically. In the closed Euclidean region two types of instantons were found. It is shown that the instantons correspond to extremal trajectories. The existence of two types of instantons gives rise to different possibilities for tunneling from Euclidean region to Minkowski region and for creation of inflationary universes.