Gravity- and non-gravity-mediated couplings in multiple-field inflation

Francis Bernardeau (1)

1 IPHT - Institut de Physique Théorique - UMR CNRS 3681

Mechanisms for the generation of primordial non-Gaussian metric fluctuations in the context of multiple-field inflation are reviewed. As long as kinetic terms remain canonical, it appears that nonlinear couplings inducing non-gaussianities can be split into two types. The extension of the one-field results to multiple degrees of freedom leads to gravity mediated couplings that are ubiquitous but generally modest. Multiple-field inflation offers however the possibility of generating non-gravity mediated coupling in isocurvature directions that can eventually induce large non-Gaussianities in the metric fluctuations. The robustness of the predictions of such models is eventually examined in view of a case study derived from a high-energy physics construction.

Mots clés: 98.80.Cq; 98.80.Es; 98.80.-k; 98.65.-r; 98.80.Bp

Francis Bernardeau. Gravity- and non-gravity-mediated couplings in multiple-field inflation. Classical and Quantum Gravity, 2010, 27 (12), pp.124004. ⟨10.1088/0264-9381/27/12/124004⟩. ⟨hal-00601891⟩