Update of D3/D7-Brane Inflation on K3 x T^2/Z_2

Understand

We update the D3/D7-brane inflation model on K3 x T^2/Z_2 with branes and fluxes.

• For this purpose, we study the low energy theory including g_s corrections to the gaugino condensate superpotential that stabilizes the K3 volume modulus.
• The gauge kinetic function is verified to become holomorphic when the original N=2 supersymmetry is spontaneously broken to N=1 by bulk fluxes.
• From the underlying classical N=2 supergravity, the theory inherits a shift symmetry which provides the inflaton with a naturally flat potential.