The Strong Multifield Slowroll Condition and Spiral Inflation
  We point out the existing confusions about the slowroll parameters and
conditions for multifield inflation. If one requires the fields to roll down
the gradient flow, we find that only articles adopting the Hubble slowroll
expansion are on the right track, and a correct condition can be found in a
recent book by Liddle and Lyth. We further analyze this condition and show that
the gradient flow requirement is stronger than just asking for a slowly
changing, quasi-de Sitter solution. Therefore it is possible to have a
multifield slowroll model that does not follow the gradient flow. Consequently,
it no longer requires the gradient to be small. It even bypasses the first
slowroll condition and some related no-go theorems from string theory. We
provide the "spiral inflation" as a generic blueprint of such inflation model
and show that it relies on a monodromy locus---a common structure in string
theory effective potentials.
