Generic no-scale inflation inspired from string theory compactifications

We propose the generic no-scale inflation inspired from string theory compactifications. We consider the Kahler potentials with an inflaton field phi, as well as one, two, and three Kahler moduli. Also, we consider the renormalizable superpotential of phi in general. We study the spectral index and tensor-to-scalar ratio in details, and find the viable parameter spaces which are consistent with the Planck and BICEP/Keck experimental data on the cosmic microwave background (CMB). The spectral index is n(s) similar or equal to 1-2/N similar to 0.965 for all models, and the tensor-to-scalar ratio r is r similar or equal to 12/N-2, 83/N-4 and 4/N-2 for the one, two and three moduli models, respectively. The particular r for two moduli model comes from the contributions of the non-negligible higher order term in potential. In the three moduli model, the scalar potential is similar to the global supersymmetry, but the Kahler potential is different. The E model with alpha = 1 and T model with alpha = 1/3 can be realized in the one modulus model and the three moduli model, respectively. Interestingly, the models with quadratic and quartic potentials still satisfy the current tight bound on r after embedding into no-scale supergravity.