DYNAMICS OF TOPOLOGICAL DEFECTS AND INFLATION

We study the dynamics of topological defects in the context of ''topol ogical inflation'' proposed by Vilenkin and Linde independently. Analy zing the time evolution of planar domain walls and of global monopoles , we find that the defects undergo inflationary expansion if eta great er than or similar to 0.33m(Pl), where eta is the vacuum expectation v alue of the Higgs field and m(Pl) is the Planck mass. This result conf irms the estimates by Vilenkin and Linde. The critical value of eta is independent of the coupling constant lambda and the initial size of t he defect. Even for defects with an initial size much greater than the horizon scale, inflation does not occur at all if eta is smaller than the critical value. We also examine the effect of gauge fields for st atic monopole solutions and find that the spacetime with a gauge monop ole has an attractive nature, contrary to the spacetime with a global monopole. It suggests that gauge fields affect the onset of inflation.