1202.3388 (I-Sheng Yang)

The Strong Multifield Slowroll Condition and Spiral Inflation    [PDF]

I-Sheng Yang

We point out and resolve the existing confusions about the slowroll
parameters and conditions for multifield inflation. We derive the correct
condition and found that at second order, requiring the field to roll down the
gradient flow imposes a stronger condition than just asking for a slowly
changing, quasi-de Sitter solution. Therefore it is possible to have multifield
slowroll models which do not follow the gradient flow. Consequently, it no
longer requires the gradient to be small. We provide the "spiral inflation" as
a generic blueprint of such inflation models and point out that it might be
common in string theory.

View original: http://arxiv.org/abs/1202.3388