Stochastic inflation and replica field theory
Abstract
We adopt methods from statistical field theory to stochastic inflation. For the example of a free test field in de Sitter and powerlaw inflation, the power spectrum of longwavelength fluctuations is computed. We study its dependence on the shape of the filter that separates long from shortwavelength modes. While for filters with infinite support the phenomenon of dimensional reductions is found on large superhorizon scales, filters with compact support return a scaleinvariant power spectrum in the infrared. Features of the power spectrum, induced by the filter, decay within a few efoldings. Thus the latetime power spectrum is independent of the filter details.
 Publication:

Physical Review D
 Pub Date:
 February 2009
 DOI:
 10.1103/PhysRevD.79.044009
 arXiv:
 arXiv:0810.5686
 Bibcode:
 2009PhRvD..79d4009K
 Keywords:

 04.62.+v;
 05.10.Gg;
 98.80.Cq;
 Quantum field theory in curved spacetime;
 Stochastic analysis methods;
 Particletheory and fieldtheory models of the early Universe;
 General Relativity and Quantum Cosmology;
 Astrophysics;
 High Energy Physics  Theory
 EPrint:
 15 pages, 14 figures