Inflationary de Sitter solutions from superstrings

Understand

In the framework of superstring compactifications with N=1 supersymmetry spontaneously broken, (by either geometrical fluxes, branes or else), we show the existence of new inflationary solutions.

• The time-trajectory of the scale factor of the metric a, the supersymmetry breaking scale m=m(Phi) and the temperature T are such that am and aT remain constant.
• These solutions request the presence of special moduli-fields: i) The universal "no-scale-modulus" Phi, which appears in all N=1 effective supergravity theories and defines the supersymmetry breaking scale m(Phi).
• ii) The modulus Phi_s, which appears in a very large class of string compactifications and has a Phi-dependent kinetic term.