Embedded topological defects in electroweak theory: From percolating networks to sphalerons

dNew defects (Z-vortices and Nambu monopoles) are found to become thermodyn amically relevant for the broken phase near to the (weakly first order) ele ctroweak phase transition, and below the crossover for higher Higgs mass. T he symmetric phase is characterized by vortex condensation (percolation). T he percolation transition persists in the crossover region. The quasiclassi cal nature of the vortices is supported by correlations with Higgs field an d gauge field energy. Sphalerons are shown to be related to monopolium boun d states.