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 ${\eta }_{\mathrm{c}\mathrm{r}}$, which is of the order of the Planck mass. In order to understand the properties of monopoles for $\eta >{\eta }_{\mathrm{c}\mathrm{r}}$, we investigate their dynamics numerically. If $\eta$ is large enough ($\gg {\eta }_{\mathrm{c}\mathrm{r}}$), a monopole expands exponentially and a wormhole structure appears around it, regardless of coupling constants and initial configuration. If $\eta$ is around ${\eta }_{\mathrm{c}\mathrm{r}}$, there are three types of solutions, depending on coupling constants and initial configuration: a monopole either expands as stated above, collapses into a black hole, or comes to take a stable configuration.