Quantum Fluctuations in Cosmology and How They Lead to a Multiverse

Abstract

This article discusses density perturbations in inflationary models, offering a pedagogical description of how these perturbations are generated by quantum fluctuations in the early universe. A key feature of inflation is that that rapid expansion can stretch microscopic fluctuations to cosmological proportions. I discuss also another important conseqence of quantum fluctuations: the fact that almost all inflationary models become eternal, so that once inflation starts, it never stops.

23 pages, 4 figures. Published in the Proceedings of the 25th Solvay Conference on Physics, "The Theory of the Quantum World," Brussels, 19--22 October 2011, edited by D. Gross, M. Henneaux, and A. Sevrin (World Scientific, 2013)

References in corpus (5)

• Generating Scale-Invariant Perturbations from Rapidly-Evolving Equation of State
• Towards a Cosmological Dual to Inflation
• The Trans-Planckian Problem for Inflationary Cosmology Revisited
• Trans-Planckian enhancements of the primordial non-Gaussianities
• Detection of transplanckian effects in the cosmic microwave background

Cited by in corpus (4)

• Inflationary paradigm after Planck 2013
• Magnetogenesis from axion inflation
• A Density Spike on Astrophysical Scales from an N-Field Waterfall Transition
• Density Perturbations in Hybrid Inflation Using a Free Field Theory Time-Delay Approach