TALK: A smooth exit form eternal inflation

ABSTRACT: 'Eternal inflation' refers to a regime deep into the phase of inflation in the early universe in which the quantum dynamics of fluctuations dominate the classical slow roll evolution. We argue that this means the classical theory of inflation breaks down in eternal inflation.
We then review the program initiated by Hawking and others to develop a quantum model of inflation. In this approach, the exit from eternal inflation is the mechanism through which the quantum universe becomes classical. Finally we discuss a remarkable recent development in this program which employs gauge-gravity duality to compute the quantum amplitudes of different shapes of the exit surface from eternal inflation. The results indicate that eternal inflation does not produce an infinite fractal-like multiverse as the naive extrapolation of the classical theory of inflation suggests, but that the exit surface is finite and reasonably smooth.