Eternal inflation and its implications

By A. Guth. 2007

403 citations recorded by the source corpus.

I summarize the arguments that strongly suggest that our universe is the product of inflation. The mechanisms that lead to eternal inflation in both new and chaotic models are described. Although the infinity of pocket universes produced by eternal inflation are unobservable, it is argued that eternal inflation has real consequences in terms of the way that predictions are extracted from theoretical models. The ambiguities in defining probabilities in eternally inflating spacetimes are reviewed, with emphasis on the youngness paradox that results from a synchronous gauge regularization technique. Although inflation is generically eternal into the future, it is not eternal into the past: it can be proven under reasonable assumptions that the inflating region must be incomplete in past directions, so some physics other than inflation is needed to describe the past boundary of the inflating region.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/24fdb9b666e2ddb66137f589bbb6e830fa425b67

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Citations in the corpus

Making predictions in the multiverse (2011, background): “Inflation ends locally, producing “pocket universes” where the fields settle into one of the vacua [3].”
Inflationary Cosmology after Planck 2013 (2014, background): “Later it was found that one of these two probability measures introduced in [58] leads to paradoxical conclusions, which are associated with the so-called “youngness problem” [165, 166].”
Multi-Verse Optimizer: a nature-inspired algorithm for global optimization (2015, background): “Every universe has an inflation rate (eternal inflation) that causes its expansion through space [18].”
The phase transition to eternal inflation (2008, background): “It is a pleasure to thank Nima Arkani-Hamed, Lotfi Boubekeur, Raphael Bousso, Ben Freivogel, Andrea Gambassi, Jaume Garriga, David Gross, Alan Guth, Andrei Linde, Matt Kleban, Raman Sundrum and Filippo Vernizzi for useful discussions and comments.”