Do We Live in a Vanilla Universe? Theoretical Perspectives on WMAP

I discuss the theoretical implications of the WMAP results, stressing WMAP’s detection of a correlation between the E-mode polarization and temperature anisotropies, which provides strong support for the overall inflationary paradigm. I point out that almost all inflationary models have a “vanilla limit,” where their parameters cannot be distinguished from a genuinely de Sitter inflationary phase. Because its findings are consistent with vanilla inflation, WMAP cannot exclude entire classes of inflationary models. Finally, I summarize hints in the current dataset that the CMB contains relics of new physics, and the possibility that we can use observational data to reconstruct the inflaton potential.