Nonlinear superhorizon curvature perturbation in generic single-field inflation

作者：Takamizu Yu ichi^*; Kobayashi Tsutomu

来源：Progress of Theoretical and Experimental Physics, 2013, 2013(6): 063E03.

DOI：10.1093/ptep/ptt033

We develop a theory of nonlinear cosmological perturbations on superhorizon scales for generic single-field inflation. Our inflation is described by the Lagrangian of the form W(X, phi) - G(X, phi) square phi with X = -partial derivative(mu)phi(mu)phi/2, which is no longer equivalent to a perfect fluid. This model is more general than k-inflation, and is called G-inflation. A general nonlinear solution for the metric and the scalar field is obtained at second order in gradient expansion. We derive a simple master equation governing the large-scale evolution of the nonlinear curvature perturbation. It turns out that the nonlinear evolution equation is deduced as a straightforward extension of the corresponding linear equation for the curvature perturbation on uniform phi hypersurfaces.

• 出版日期2013-6