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