D6-branes and axion monodromy inflation
  We develop new scenarios of large field inflation in type IIA string
compactifications in which the key ingredient is a D6-brane that creates a
potential for a B-field axion. The potential has the multi-branched structure
typical of F-term axion monodromy models and, near its supersymmetric minima,
it is described by a 4d supergravity model of chaotic inflation with a
stabiliser field. The same statement applies to the D6-brane Wilson line, which
can also be considered as an inflaton candidate. We analyse both cases in the
context of type IIA moduli stabilisation, finding an effective potential for
the inflaton system and a simple mechanism to lower the inflaton mass with
respect to closed string moduli stabilised by fluxes. Finally, we compute the
B-field potential for trans-Planckian field values by means of the DBI action.
The effect of Planck suppressed corrections is a flattened potential which, in
terms of the compactification parameters, interpolates between linear and
quadratic inflation. This renders the cosmological parameters of these models
compatible with current experimental bounds, with the tensor-to-scalar ratio
ranging as 0.08 < r < 0.12
