TY - JOUR
T1 - Breakdown of semiclassical methods in de Sitter space
AU - Burgess, C. P.
AU - Holman, R.
AU - Leblond, L.
AU - Shandera, S.
PY - 2010/10
Y1 - 2010/10
N2 - Massless interacting scalar fields in de Sitter space have long been known to experience large fluctuations over length scales larger than Hubble distances. A similar situation arises in condensed matter physics in the vicinity of a critical point, and in this betterunderstood situation these large fluctuations indicate the failure in this regime of mean-field methods. We argue that for non-Goldstone scalars in de Sitter space, these fluctuations can also be interpreted as signaling the complete breakdown of the semi-classical methods widely used throughout cosmology. By power-counting the infrared properties of Feynman graphs in de Sitter space we find that for a massive scalar interacting through a A λφ4 interaction, control over the loop approximation is lost for masses smaller than m ≃√λH/2φ, where H is the Hubble scale. We briefly discuss some potential implications for inflationary cosmology.
AB - Massless interacting scalar fields in de Sitter space have long been known to experience large fluctuations over length scales larger than Hubble distances. A similar situation arises in condensed matter physics in the vicinity of a critical point, and in this betterunderstood situation these large fluctuations indicate the failure in this regime of mean-field methods. We argue that for non-Goldstone scalars in de Sitter space, these fluctuations can also be interpreted as signaling the complete breakdown of the semi-classical methods widely used throughout cosmology. By power-counting the infrared properties of Feynman graphs in de Sitter space we find that for a massive scalar interacting through a A λφ4 interaction, control over the loop approximation is lost for masses smaller than m ≃√λH/2φ, where H is the Hubble scale. We briefly discuss some potential implications for inflationary cosmology.
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U2 - 10.1088/1475-7516/2010/10/017
DO - 10.1088/1475-7516/2010/10/017
M3 - Article
AN - SCOPUS:78449294793
SN - 1475-7516
VL - 2010
JO - Journal of Cosmology and Astroparticle Physics
JF - Journal of Cosmology and Astroparticle Physics
IS - 10
M1 - 017
ER -