On Non-Perturbative Effects at the High-Temperature Electroweak Phase Transition

It is argued that confining effects in 3-dimensional non-Abelian gauge theories (high-temperature limit of 4-dimensional ones) imply the existence of the condensates of the gauge and Higgs fields in 3-d vacuum. This non-perturbative effect can decrease the energy of the phase with unbroken symmetry and may result in the creation of a barrier separating the broken and unbroken phases. Thus the high-temperature phase transitions in gauge theories can be stronger first order than is expected from perturbation theory. The applications of these results to electroweak baryogenesis are briefly discussed.