Quasi-Single Field Inflation and Non-Gaussianities

By Xingang Chen, Yi Wang. 2009

596 citations recorded by the source corpus.

In quasi-single field inflation models, massive isocurvature modes, that are coupled to the inflaton and have mass of order the Hubble parameter, can have nontrivial impacts on density perturbations, especially non-Gaussianities. We study a simple example of quasi-single field inflation in terms of turning inflaton trajectory. Large bispectra with a one-parameter family of novel shapes arise, lying between the well-known local and equilateral shape. The trispectra can also be very large and its magnitude tNL can be much larger than fNL2.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/cb4c3e4624bdc08f3c2db39c49bc8ebe2ddea5e1

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Citations in the corpus

Effective field theory approach to quasi-single field inflation and effects of heavy fields (2012, methodology): “For this purpose, we first discuss the original model of quasi-single field inflation [29, 30], and then, we investigate the effects of heavy particles during inflation.”
Schwinger-Keldysh diagrammatics for primordial perturbations (2017, methodology): “3 and appendix C of [22] for explanation), but the integral here is organized in a much more economic form.”
The DESI Experiment Part I: Science,Targeting, and Survey Design (2016, background): “Recently, a number of inflationary models have been proposed which predict a potentially observable level of non-Gaussianity, these include those from fast-roll inflation [130, 131, 132, 133, 134], quasi-single field inflation [135, 136], warm inflation [137, 138], and non-Bunch-Davies or excited in”
Features of heavy physics in the CMB power spectrum (2010, background): “We find that the overall effect of having a constant turn is simply to normalise the amplitude of the spectrum, without modifying the usual single field dependence of the spectral index nR in terms of the slow-roll parameters and η|| (see also [52, 53]): nR − 1 = 2η|| − 4 .”
Signature of supersymmetry from the early universe (2011, methodology): “QSFI couples a massless Goldstone mode, Lπ = −(1) 2(∂μπc)(2), to a massive isocurvaton mode, Lσ = −(1)2(∂μσ)(2) − 12m(2)σσ(2), through a quadratic mixing term Lmix, which [11] chose as Lmix = ρπ̇cσ.”
The cosmological bootstrap: inflationary correlators from symmetries and singularities (2018, unknown): “in [49–51, 54].”
Prospects for cosmological collider physics (2016, background): “The possible amplitudes of these bispectra span a wide range of values, and strongly depend on the nature of couplings in the model [2, 3, 20, 29].”
Planck 2018 results. IX. Constraints on primordial non-Gaussianity (2019, background): “Measuring primordial NG can allow us to pin down masses and spins of the particle content present during inflation, making inflation a powerful cosmological collider (Chen 2010b; Chen & Wang 2010; Noumi et al. 2013; Arkani-Hamed & Maldacena 2015; Baumann et al. 2018; Arkani-Hamed et al. 2018).”
The Cosmological Bootstrap: Spinning correlators from symmetries and factorization (2020, background): “Such a classification would provide the conceptual foundation for the discipline of “cosmological collider physics” [13–39], and facilitate a deeper understanding of theoretical constraints on cosmological correlators.”
Mass hierarchies and non-decoupling in multi-scalar field dynamics (2010, unknown): “[20, 21].”
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].”
Phenomenology of a pseudo-scalar inflaton: naturally large nongaussianity (2011, methodology): “To obtain observable nongaussianity, previous studies have invoked non-standard field theories (involving small sounds speed [23] or higher derivatives [5]), or initial conditions [23, 24, 25, 26], potentials with sharp features [27, 28], dissipative effects [3], fine-tuned inflationary trajectories”