Large Field Inflation from Axion Mixing
  We study the general multi-axion systems, focusing on the possibility of
large field inflation driven by axions. We find that through axion mixing from
a non-diagonal metric on the moduli space and/or from St\"uckelberg coupling to
a U(1) gauge field, an effectively super-Planckian decay constant can be
generated without the need of "alignment" in the axion decay constants. We also
investigate the consistency conditions related to the gauge symmetries in the
multi-axion systems, such as vanishing gauge anomalies and the potential
presence of generalized Chern-Simons terms. Our scenario applies generally to
field theory models whose axion periodicities are intrinsically sub-Planckian,
but it is most naturally realized in string theory. The types of axion mixings
invoked in our scenario appear quite commonly in D-brane models, and we present
its implementation in type II superstring theory. Explicit stringy models
exhibiting all the characteristics of our ideas are constructed within the
frameworks of Type IIA intersecting D6-brane models on T6/OR and Type IIB
intersecting D7-brane models on Swiss-Cheese Calabi-Yau orientifolds.
