Dynamics of gravitating magnetic monopoles

According to previous work on magnetic monopoles, static regular solutions are nonexistent if the vacuum expectation value of the Higgs field \eta is larger than a critical value \eta_{{\rm cr}}, which is of the order of the Planck mass. In order to understand the properties of monopoles for \eta>\eta_{{\rm cr}}, we investigate their dynamics numerically and classify those dynamical solutions into three types as follows. If \eta is larger than another critical value \eta_{{\rm inf}}~(>\eta_{{\rm cr}}), a monopole inflates and a wormhole structure appears around it. In the case of \eta_{{\rm cr}}<\eta<\eta_{{\rm inf}}, inflation does not occur and the dynamics depend on the ratio of the Higgs self coupling constant \lambda and the gauge coupling constant e^2: if \lambda/e^2\stackrel{<}{\sim}1, a monopole just shrinks and becomes a black hole; otherwise, a monopole approaches a stable configuration