Eternal Inflation: The Inside Story

Abstract

Motivated by the lessons of black hole complementarity, we develop a causal patch description of eternal inflation. We argue that an observer cannot ascribe a semiclassical geometry to regions outside his horizon, because the large-scale metric is governed by the fluctuations of quantum fields. In order to identify what is within the horizon, it is necessary to understand the late time asymptotics. Any given worldline will eventually exit from eternal inflation into a terminal vacuum. If the cosmological constant is negative, the universe crunches. If it is zero, then we find that the observer's fate depends on the mechanism of eternal inflation. Worldlines emerging from an eternal inflation phase driven by thermal fluctuations end in a singularity. By contrast, if eternal inflation ends by bubble nucleation, the observer can emerge into an asymptotic, locally flat region. As evidence that bubble collisions preserve this property, we present an exact solution describing the collision of two bubbles.

17 pages, 12 figures; v2, PRD format

References in corpus (1)

• Holographic probabilities in eternal inflation

Cited by in corpus (26)

• TASI Lectures on the Cosmological Constant
• A Measure of de Sitter Entropy and Eternal Inflation
• Predicting the Cosmological Constant from the Causal Entropic Principle
• Predicting the cosmological constant with the scale-factor cutoff measure
• Properties of the scale factor measure
• Towards observable signatures of other bubble universes
• Accidental Inflation in String Theory
• Boltzmann babies in the proper time measure
• The Volume of the Universe after Inflation and de Sitter Entropy
• Complementarity in the Multiverse
• A measure of the multiverse
• Towards observable signatures of other bubble universes II: Exact solutions for thin-wall bubble collisions
• Constructing a counterexample to the black hole complementarity
• Surviving the crash: assessing the aftermath of cosmic bubble collisions
• Landscape Predictions from Cosmological Vacuum Selection
• Stationary Measure in the Multiverse
• The Born Rule Dies
• Cosmological Measures without Volume Weighting
• Eternal Inflation, past and future
• Future Foam
• Entropy and initial conditions in cosmology
• The Census Taker's Hat
• Reheating-volume measure for random-walk inflation
• Reheating-volume measure in the landscape
• Life, the Universe, and almost Everything: Signs of Cosmic Design?
• Phase Diagram for Nflation