Quasi-single and multiple field inflation

Yi Wang (McGill)

ABSTRACT

The talk consists of two parts:

(1) Quasi-single inflation, where the isocurvature direction has mass of order

Hubble parameter. In this case the homogeneous background behaves like single

field, but new features as non-Gaussianity show up in the perturbation level.

(2) Multi-stream inflation, where the inflationary trajectory bifurcates. Position

space features from inflation becomes possible from the bifurcation. The

observational effects include non-Gaussianity, feature and asymmetry on the CMB.

A bound for inflation in the string landscape is also derived from the absent of too

many bifurcations.