2010/11/30 by Paul McFadden, Kostas Skenderis · 2 citations
Physics and Astronomy · #hep-th #astro-ph.CO #gr-qc
paper · pdf · doi:10.1088/1475-7516/2011/05/013
published as JCAP 1105:013,2011 · 42 pages, 2 figs, published version
arxiv created 2011/05/12 · arxiv updated 2011/05/16
We investigate the non-Gaussianity of primordial cosmological perturbations within our recently proposed holographic description of inflationary universes. We derive a holographic formula that determines the bispectrum of cosmological curvature perturbations in terms of correlation functions of a holographically dual three-dimensional non-gravitational quantum field theory (QFT). This allows us to compute the primordial bispectrum for a universe which started in a non-geometric holographic phase, using perturbative QFT calculations. Strikingly, for a class of models specified by a three-dimensional super-renormalisable QFT, the primordial bispectrum is of exactly the factorisable equilateral form with fnleq=5/36, irrespective of the details of the dual QFT. A by-product of this investigation is a holographic formula for the three-point function of the trace of the stress-energy tensor along general holographic RG flows, which should have applications outside the remit of this work.