Testing Inflation with the Cosmic Background Radiation

Abstract

In inflation cosmologies, cosmic structure develops through the gravitational instability of the inevitable quantum noise in primordial scalar fields. I show how the acceleration of the universe defines the shape of the primordial spectrum of gravitational metric and scalar field fluctuations. I assess how we can determine the shape and overall amplitude over the five decades or so of spatial wavelengths we can probe, and use current data ... to show how far we are in this program. Broad-band power amplitudes are given for CMB anisotropy detections up to spring 1994 ... I show that COBE band-powers found with full Bayesian analysis of the $53,90,31$ $a$+$b$ GHz first year DMR (and FIRS) maps are in good agreement, and are essentially independent of spectral slope and degree of (sharp) signal-to-noise filtering. Further, after (smooth) optimal signal-to-noise filtering (\ie Weiner-filtering), the different DMR maps reveal the same large scale features and correlation functions with little dependence upon slope. However, the most probable slope depends upon how the maps are filtered: with no filtering whatsoever, the slope is high, but the power is not described by a single-slope law; as filtering is increased, the index moves nearer to inflation predictions. in {\it Relativistic Cosmology}, ed. M. Sasaki, Academic Press (1994) Proc. 8th Nishinomiya-Yukawa Memorial Symposium, Japan, October 1993