All scalar degrees of freedom that have been employed so far turned out to be composite. In particular, the Cooper pairs – a composite of two electrons – in an ordinary superconductivity and the chiral condensate in the ordinary QCD are two time-honored examples. A thorough and comprehensive study over the past few decades of strongly interacting field theories poses a considerable challenge for theoretical physicists. Strong dynamics is intensively studied in extensions of the standard model of particle interactions while very little is known in cosmology.
Inspired by the composite Higgs paradigms, it would be of great interest to imagine a natural strong dynamics underlying the cosmic inflation. In this work, we investigate a number of models of inflation in which the inflaton emerges as a composite state stemming from different kinds of four-dimensional strongly interacting gauge theories. We begin by briefly reviewing the standard cosmology and inflationary paradigm. To be more relevant to phenomenology, we preliminarily provide a road map to non-Gaussian effects.
We then summarize a compelling model of dynamical electroweak symmetry breaking, namely the minimal walking technicolor (MWT) theory. We briefly review the basic concepts of the Yang-Mills theory. We propose minimal walking and glueball inflationary models. We show that they are all viable to obtain successful inflation via non-minimal coupling to gravity. We discover that the compositeness scale of inflation is of the order of the expected grand unification scale.