Figure 1

Plot of the Hubble parameter $H$ (left panel) and the phase diagram ($\varphi$, $\dot{\varphi }$) (right panel) for various initial data with $m=1/4$, $\kappa =1/4$, and $\lambda =1$. In the left panel, $H=0$ at the very center. The contours are separated by $\Delta H=0.1$. The blue color (the regions at the center, the top and the bottom) represents small $H$. The reddest part (the regions at the left and the right) denotes the region of $H>1$. The intermediate parts denote the region of $0.1\le H\le 1$. The region in white is physically forbidden. In the right panel, the blue-shaded region (at the top and the bottom) denotes the physically forbidden region bounded by the MPS (black thick line). The other curves denote the evolution of the perturbed scalar field from the MPS with other initial conditions. The solid curves denote the evolution starting from the upper left region, and the dashed curves denote the evolution starting from the bottom right region. The attractor trajectory is the curve to which the nearby paths converge. The Universe undergoes chaotic inflation along the attractor trajectory until the scalar field becomes small enough. The high-curvature regime is denoted by the shaded quantum-gravity (QG) region. (The parameters for the figure, in particular, $m=1/4$, have been chosen for the graphical purpose. In reality, $m\sim {10}^{-5}$ with which inflation provides sufficient $e$ foldings if $|{\varphi }_i|\gtrsim 10$.)Reuse & Permissions