Dilaton-axion modular inflation in supergravity

Dilaton and axion are ubiquitous in extended supergravities and closed superstrings. We propose new models of modular inflation in four-dimensional $N=1$ supergravity coupled to the chiral dilaton-axion-goldstino supermultiplet, which fit some necessary conditions of superstring cosmology. The model parameters are tuned to obey precision measurements of the cosmic microwave background radiation. We employ the modular-invariant superpotentials and asymptotically modular-invariant Kähler potentials, and achieve axion stabilization with high-scale supersymmetry breaking.