The upper bound on the tensor-to-scalar ratio consistent with quantum gravity

Lina Wu,Qing Gao,Yungui Gong,Yiding Jia,Tianjun Li

Figure 2. The evolution of Hubble flow slow-roll parameters ${\epsilon }_{1}^{H}$ (blue solid line) and ${\epsilon }_{2}^{H}$ (red dashed line).