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Inflationary spacetimes are not past-complete
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Inflationary spacetimes are not past-complete
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Many inflating spacetimes are likely to violate the weak energy condition, a key assumption of singularity theorems. Here we offer a simple kinematical argument, requiring no energy condition, that a cosmological model which is inflating -- or just expanding sufficiently fast -- must be incomplete in null and timelike past directions. Specifically, we obtain a bound on the integral of the Hubble parameter over a past-directed timelike or null geodesic. Thus inflationary models require physics other than inflation to describe the past boundary of the inflating region of spacetime.
Forward citations
Cited by 14 Pith papers
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Affine ANEC selects the closed FRW branch for geodesically complete cosmology
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Birth of Inflationary Universes via Wineglass Wormholes and their No-Boundary Relatives
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Open case for a closed universe
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Semi-infinite slow contraction (ε>3) is past-complete and horizon-free, asymptotes to Minkowski, evades BGV, and stays stable, unlike contracting de Sitter.
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Geodesically Complete Curvature-Bounce Inflation
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Causal Horizons, Geodesic Completeness and Stability in Slow Contraction Cosmology
Semi-infinite slow contraction (ε>3) eliminates particle horizons, asymptotes to Minkowski in the past, remains geodesically complete and BGV-evading, and supplies stable low-entropy initial conditions after a non-sin...
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