Inflation in the Postmodern Era

In this lecture I will review some recent progress in improving the accuracy of the calculation of density perturbations resulting from inflation.Comment: 21-page LaTeX file for proceedings of the Erice School ``Astrofundamental Physics.'' Four postscript figures, figi.ps (i=1 to 4), included using eps

Fluctuation driven electroweak phase transition

We examine the dynamics of the electroweak phase transition in the early Universe. For Higgs masses in the range 46 less than or = M sub H less than or = 150 GeV and top quark masses less than 200 GeV, regions of symmetric and asymmetric vacuum coexist to below the critical temperature, with thermal equilibrium between the two phases maintained by fluctuations of both phases. We propose that the transition to the asymmetric vacuum is completed by percolation of these subcritical fluctuations. Our results are relevant to scenarios of baryogenesis that invoke a weakly first-order phase transition at the electroweak scale

Cosmic Microwave Background Observations as a Way to Discriminate Among Inflation Models

The upcoming satellite missions MAP and Planck will measure the spectrum of fluctuations in the Cosmic Microwave Background with unprecedented accuracy. We discuss the prospect of using these observations to distinguish among proposed models of inflationary cosmology.Comment: To appear in the proceedings of the XXXIIIrd Rencontres de Moriond, "Fundamental Parameters in Cosmology", 17-24 January, Les Arcs, France. 6 Pages, 2 figures, uses moriond.st