19 Jan 2008 | Xingang Chen, Min-xin Huang, Shamit Kachru, and Gary Shiu
The paper by Chen, Huang, Kachru, and Shiu explores the non-Gaussianities in primordial scalar fluctuations from single-field inflationary models in Einstein gravity. The authors consider models where the inflaton Lagrangian is an arbitrary function of the scalar field and its first derivative, with an arbitrary sound speed. They find that under reasonable assumptions, the non-Gaussianity is determined by five parameters. In specific limits of the parameter space, distinct "shapes" of non-Gaussianity emerge, some of which may become observable in future experiments, particularly in models with a small sound speed. The paper also discusses various inflationary models, including slow-roll inflation, DBI inflation, and kinetic-driven inflation, and provides detailed calculations of the non-Gaussianities in these models. The authors emphasize the importance of non-Gaussianities as a probe of the inflationary vacuum and the potential for string-inspired models to yield characteristic non-Gaussian signatures.The paper by Chen, Huang, Kachru, and Shiu explores the non-Gaussianities in primordial scalar fluctuations from single-field inflationary models in Einstein gravity. The authors consider models where the inflaton Lagrangian is an arbitrary function of the scalar field and its first derivative, with an arbitrary sound speed. They find that under reasonable assumptions, the non-Gaussianity is determined by five parameters. In specific limits of the parameter space, distinct "shapes" of non-Gaussianity emerge, some of which may become observable in future experiments, particularly in models with a small sound speed. The paper also discusses various inflationary models, including slow-roll inflation, DBI inflation, and kinetic-driven inflation, and provides detailed calculations of the non-Gaussianities in these models. The authors emphasize the importance of non-Gaussianities as a probe of the inflationary vacuum and the potential for string-inspired models to yield characteristic non-Gaussian signatures.