ELECTRICAL-CONDUCTIVITY IN THE EARLY UNIVERSE

We calculate the electrical conductivity in the early universe at temp eratures below as well as above the electroweak vacuum scale, T-c=100 GeV. Debye and dynamical screening of electric and magnetic interactio ns leads to a finite conductivity, sigma(el)similar to T/alpha In(1/al pha), at temperatures well below T-c. At temperatures above, W+/- char ge-exchange processes-analogous to color exchange through gluons in QC D-effectively stop left-handed charged leptons. However, right-handed leptons can carry current, resulting in sigma(el)/T being only a facto r similar to cos(4) theta(W) Smaller than at temperatures below T-c. [ S0556-2821(97)06620-4].