http://arxiv.org/abs/1910.04741
The recently proposed trans-Planckian censorship conjecture (TCC) seems to require that the energy scale of inflation is significantly lower than the Planck scale $(H_\text{inf}<10^{-20} M_\text{Pl})$. This, in turn, implies that the scalar-to-tensor ratio for inflation is negligibly small, independent of assumptions of slow-roll or even of having a single scalar field. After demonstrating the robustness and generality of these bounds, we show that having an excited initial state for cosmological perturbations seems to be a way out of this problem for models of inflation.
S. Brahma
Fri, 11 Oct 19
52/76
Comments: 15 pages, comments welcome