Speaker
Description
We show that in no-scale models in string theory, the flat, expanding cosmological evolutions found at the quantum level can be attracted to a "quantum no-scale regime" (QNSR), where the no-scale structure is restored asymptotically. In this regime, the quantum effective potential is dominated by the classical kinetic energies of moduli fields. To be specific, we find that all initially expanding cosmological evolutions along which the 1-loop potential V_{1-loop} is positive are attracted to the QNSR describing a flat, ever-expanding universe. On the contrary, when V_{1-loop} can reach negative values, the expansion comes to a halt and the universe eventually collapses into a Big Crunch, unless the initial conditions are tuned in a tiny region of the phase space. This suggests that flat, ever-expanding universes with positive potentials are way more natural than their counterparts with negative potentials.
