Inflation: Theory and Observations
  Cosmic inflation provides a window to the highest energy densities accessible
in nature, far beyond those achievable in any realistic terrestrial experiment.
Theoretical insights into the inflationary era and its observational probes may
therefore shed unique light on the physical laws underlying our universe. This
white paper describes our current theoretical understanding of the inflationary
era, with a focus on the statistical properties of primordial fluctuations. In
particular, we survey observational targets for three important signatures of
inflation: primordial gravitational waves, primordial non-Gaussianity and
primordial features. With the requisite advancements in analysis techniques,
the tremendous increase in the raw sensitivities of upcoming and planned
surveys will translate to leaps in our understanding of the inflationary
paradigm and could open new frontiers for cosmology and particle physics. The
combination of future theoretical and observational developments therefore
offer the potential for a dramatic discovery about the nature of cosmic
acceleration in the very early universe and physics on the smallest scales.
