Can the universe afford inflation?

Abstract

Cosmic inflation is envisioned as the ``most likely'' start for the observed universe. To give substance to this claim, a framework is needed in which inflation can compete with other scenarios and the relative likelihood of all scenarios can be quantified. The most concrete scheme to date for performing such a comparison shows inflation to be strongly disfavored. We analyze the source of this failure for inflation and present an alternative calculation, based on more traditional semiclassical methods, that results in inflation being exponentially favored. We argue that reconciling the two contrasting approaches presents interesting fundamental challenges, and is likely to have a major impact on ideas about the early universe.

10 pages including 1 figure and two appendices. V2: Final version accepted for publication in PRD. The content and conclusions are unchanged. References have been added and typos corrected. A new appendix outlines the relationship of this paper to issues previously raised by Penrose and others

References in corpus (3)

• First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Implications for Inflation
• Disturbing Implications of a Cosmological Constant
• Recurrent Nightmares?: Measurement Theory in de Sitter Space

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