Non-Gaussianities in single field inflation and their optimal limits from the WMAP 5-year data

By L. Senatore, Kendrick M. Smith, M. Zaldarriaga. 2009

429 citations recorded by the source corpus.

Using the recently developed effective field theory of inflation, we argue that the size and the shape of the non-Gaussianities generated by single-field inflation are generically well described by two parameters: fNLequil, which characterizes the size of the signal that is peaked on equilateral configurations, and fNLorthog, which instead characterizes the size of the signal which is peaked both on equilateral configurations and flat-triangle configurations (with opposite signs). The shape of non-Gaussianities associated with fNLorthog is orthogonal to the one associated to fNLequil, and former analysis have been mostly blind to it. We perform the optimal analysis of the WMAP 5-year data for both of these parameters. We find no evidence of non-Gaussianity, and we have the following constraints: −125 ≤ fNLequil ≤ 435, −369 ≤ fNLorthog ≤ 71 at 95% CL. We show that both of these constraints can be translated into limits on parameters of the Lagrangian of single-field inflation. For one of them, the speed of sound of the inflaton fluctuations, we find that it is either bounded to be cs ≥ 0.011 at 95% CL. or alternatively to be so small that the higher-derivative kinetic term dominate at horizon crossing. We are able to put similar constraints on the other operators of the inflaton Lagrangian.

Subfields: Astronomy and Astrophysics, Oceanography

View Paper: https://www.semanticscholar.org/paper/431f1b9b213cdfebb616ca25ffa52c98ad031727

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Citations in the corpus

Constraining primordial non-Gaussianity with future galaxy surveys (2011, background): “These configurations or a mixture thereof can be produced under different inflationary scenarios, see e.g. Babich et al. (2004); Senatore et al. (2010) for more details.”
Primordial Non-Gaussianities from Inflation Models (2010, methodology): “By construction, this ansatz is much more orthogonal to the local form (with correlation ∼ 0) than the Sorth ansatz currently used in [1, 175].”
The Effective Field Theory of Large Scale Structures at two loops (2013, background): “To put forth a concrete example, limits on inflationary non-Gaussianities of the equilateral [28] or orthogonal [29] kind, assuming a cosmic variance”
SEVEN-YEAR WILKINSON MICROWAVE ANISOTROPY PROBE (WMAP) OBSERVATIONS: COSMOLOGICAL INTERPRETATION (2010, methodology): “Senatore et al. (2010) NL , Note that these are not the most general forms one can write down, and there are other forms which would probe different aspects of the physics of inflation (Moss & Xiong 2007; Moss & Graham 2007; Chen et al. 2007; Holman & Tolley 2008; Chen & Wang 2010; Chen & Wang…”
Testing Inflation with Large Scale Structure: Connecting Hopes with Reality (2014, background): “8, the equilateral template [6], f eq NL = −42± 75, and the ortogonal template [7], f NL = −25 ± 39 .”
On the statistics of biased tracers in the Effective Field Theory of Large Scale Structures (2015, background): “[44] there are two templates for the three point function that is induced by f NL .”
CMB-S4 Science Case, Reference Design, and Project Plan (2019, background): “in which inflaton fluctuations have non-trivial self-interactions [92, 93, 94, 95, 96, 83] or couplings between the inflaton and other (potentially massive) degrees of freedom [97, 98, 99, 100, 101, 89, 85].”
Planck 2018 results. IX. Constraints on primordial non-Gaussianity (2019, methodology): “Here M3 is the amplitude of the operator π̇3 (see Senatore et al. 2010; Chen et al. 2007b; Chen 2010b), with the dimensionless parameter c̃3(c−2s − 1) = 2M43c 2 s/(ḢM 2 Pl) (Senatore et al. 2010).”
The effective field theory of multifield inflation (2010, methodology): “predictions and of the detectability thresholds, along the lines of what done in [3] for single-clock inflation, to future work.”
Planck 2015 results. XVII. Constraints on primordial non-Gaussianity (2015, neutral): “The “orthogonal” shape template is (Senatore et al. 2010) BorthoΦ (k1, k2, k3) = 6A 2 f orthoNL × − 3k4−ns1 k4−ns2 − 3 k4−ns2 k 4−ns 3 − 3 k4−ns3 k 4−ns 1 − 8 (k1k2k3)2(4−ns)/3 + 3 k(4−ns)/31 k 2(4−ns)/3 2 k 4−ns 3 + (5 perm.)”
Cosmology and Fundamental Physics with the Euclid Satellite (2012, background): “An example of such a shape is the orthogonal shape proposed in [1074].”
NINE-YEAR WILKINSON MICROWAVE ANISOTROPY PROBE (WMAP) OBSERVATIONS: FINAL MAPS AND RESULTS (2012, background): “The coefficients in the action (56) can be related to the parameters f eqNL, f orth NL by calcu- lating the bispectra generated by the cubic operators π̇3 and π̇(∂iπ) 2, and projecting them onto the basis of template bispectra (Senatore et al. 2010).”
Large-scale bias and efficient generation of initial conditions for nonlocal primordial non-Gaussianity (2011, background): “More precisely, this template is only a good approximation to the orthogonal shape away from the squeezed limit, otherwise more complicated templates should be used [15, 16].”
Solid Inflation (2012, background): “However, we find a small cosine with the orthogonal template of [21]:”