Dynamics of cosmic necklaces

We perform numerical simulations of cosmic necklaces (systems of monopoles connected to two strings each) and investigate the conditions under which m onopoles annihilate. When the total monopole energy is large compared to th e string energy, we find that the string motion is no longer periodic, and thus the strings will be chopped up by self intersection. When the total mo nopole energy is much smaller than the string energy, the string motion is periodic, but that of the monopoles is not, and thus the monopoles travel a long the string and annihilate with each other. (C) 2001 Elsevier Science B .V. All rights reserved.