Quantum contributions to cosmological correlations

By S. Weinberg. 2005

911 citations recorded by the source corpus.

The 'in-in' formalism is reviewed and extended, and applied to the calculation of higher-order Gaussian and non-Gaussian correlations in cosmology. Previous calculations of these correlations amounted to the evaluation of tree graphs in the in-in formalism; here we also consider loop graphs. It turns out that for some though not all theories, the contributions of loop graphs as well as tree graphs depend only on the behavior of the inflaton potential near the time of horizon exit. A sample one-loop calculation is presented.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/e1a447901658319465298a8312786652e8c15561

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Citations in the corpus

Symmetries and loops in inflation (2012, background): “This question was first raised by Weinberg in [6, 7].”
Primordial Non-Gaussianities from Inflation Models (2010, methodology): “We start with the in-in formalism [40–45], following Weinberg’s presentation [45].”
Resonant non-gaussianity (2010, background): “To leading order in perturbation theory, the three-point function in the “in-in” formalism [22] (see also [23,24] and references therein) is given by 〈R(k1, t)R(k2, t)R(k3, t)〉 = −i ∫ t”
The Cosmological Optical Theorem (2020, neutral): “Notice that these are two of the four propagators that appear in the in-in formalism [37], but they can be easily related to the propagator of the wavefunction method via, G(k, η, η′) = G++(k, η, η′)− i σ+(k, η)σ+(k, η′) σ−(k, η0) σ+(k, η0) .”
Infrared effects in inflationary correlation functions (2010, methodology): “In calculating loop corrections, Weinberg [54, 55] made use of dimensional regularization.”
Signature of supersymmetry from the early universe (2011, methodology): “s and provides a physical understanding of the origin of the eect. Of course, both approaches will yield the same results. B.1 Amplitude of the Bispectrum We use the \in-in formalism" (see e.g. [52,53]) to compute the bispectrum h3(0)i= h j Texp i Z 0 1 H I(˝)d˝ 3 I(0) Texp i Z 0 1 H I(˝)d”
Semiclassical relations and IR effects in de Sitter and slow-roll space-times (2010, background): “18) (7)The curvature perturbation R is related to our ζ by R = −ζ as discussed in the second footnote of [29] around eq.”
Galileon inflation (2010, background): “17) are discussed at several places in the literature, to which we refer for calculational details [47, 65, 72].”
Quasi-single field inflation with large mass (2012, background): “1, and the corresponding terms in the in-in formalism (see [14,15] for review) are”
De Sitter space and eternity (2007, background): “In [1] I tried to evaluate the infrared corrections to the cosmological constant in the Euclidean signature, while in the later work [5] and [ 7 ] a number of results were obtained in the in-in formalism.”
On soft limits of inflationary correlation functions (2012, methodology): “We compute correlation functions of products of field operators, Q(τ), in the in-in formalism [55, 56]”
Primordial non-Gaussianities from multiple-field inflation (2005, background): “The details of this were recently explored by Weinberg [63], who showed that in a large class of multi-field models such integrals are dominated by the epoch of horizon crossing, even beyond tree-level in perturbation theory.”