Inflaton as an auxiliary topological field in a QCD-like system

Abstract

We propose a new scenario for early cosmology, where inflationary de Sitter phase dynamically occurs. The effect emerges as a result of dynamics of the topologically nontrivial sectors in expanding universe. Technically the effect can be described in terms of the auxiliary fields which effectively describe the dynamics of the topological sectors in a gauge theory. Inflaton in this framework is an auxiliary topological non-propagating field with no canonical kinetic term, similar to known topologically ordered phases in condensed matter systems. We explain many deep questions in this framework using the so-called weakly coupled "deformed QCD" toy model.While this theory is weakly coupled gauge theory, it preserves all the crucial elements of strongly interacting gauge theory, including confinement, nontrivial $\theta$ dependence, degeneracy of the topological sectors, etc. We discuss a specific realization of these ideas using a scaled up version of QCD, coined as \qcd, with the scale M_{PL}\gg \Lbar\gg \sqrt[3]{M_{EW}^2M_{PL}}\sim 10^8 {\mathrm{GeV}}. If no other fields are present in the system de Sitter phase will be the final destination of evolution of the universe. If other interactions are present in the system, the inflationary de Sitter phase lasts for a finite period of time. The inflation starts from the thermal equilibrium state long after the \qcd -confinement phase transition at temperature T_{i}\sim \Lbar\sqrt{\frac{\Lbar}{M_{PL}}}. The end of inflation is triggered by the coupling with gauge bosons from the Standard Model. The corresponding interaction is unambiguously fixed by the triangle anomaly. Number of e-folds in the \qcd-inflation framework is determined by the gauge coupling constant at the moment of inflation, and estimated as N_{\rm inf}\sim \alpha_s^{-2}\sim 10^2.