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Evidence for the presence of extra fields during inflation may be found in the anisotropies of the scalar and tensor spectra across a vast range of scales. Indeed, beyond the single-field slow-roll paradigm, a long tensor mode can modulate…

Cosmology and Nongalactic Astrophysics · Physics 2020-02-19 Emanuela Dimastrogiovanni , Matteo Fasiello , Gianmassimo Tasinato

We revisit the squeezed-limit non-Gaussianity in the single-field non-attractor inflation models from the viewpoint of the cosmological soft theorem. In the single-field attractor models, inflaton's trajectories with different initial…

High Energy Physics - Theory · Physics 2023-12-06 Teruaki Suyama , Yuichiro Tada , Masahide Yamaguchi

Enhancements of primordial curvature fluctuations in single field inflation often involve departures from attractor trajectories in the phase space. We study enhancement/suppression of primordial fluctuations in one of the simplest models…

Cosmology and Nongalactic Astrophysics · Physics 2023-09-25 Guillem Domènech , Gerson Vargas , Teófilo Vargas

An important prediction of inflation is the production of a primordial stochastic gravitational wave background. Observing this background is challenging due to the weakness of the signal and the simultaneous presence of an astrophysical…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-18 Sofia P. Corbà

The gravitationally enhanced friction can reduce the speed of the inflaton to realize an ultra-slow-roll inflation, which will amplify the curvature perturbations. The amplified perturbations can generate a sizable amount of primordial…

General Relativity and Quantum Cosmology · Physics 2022-10-27 Li-Yang Chen , Hongwei Yu , Puxun Wu

We show that an inflation model in which a spectator axion field is coupled to an SU(2) gauge field produces a large three-point function (bispectrum) of primordial gravitational waves, $B_{h}$, on the scales relevant to the cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2018-06-06 Aniket Agrawal , Tomohiro Fujita , Eiichiro Komatsu

We study the degree to which the cosmic microwave background (CMB) can be used to constrain primordial non-Gaussianity involving one tensor and two scalar fluctuations, focusing on the correlation of one polarization $B$ mode with two…

Cosmology and Nongalactic Astrophysics · Physics 2016-06-15 P. Daniel Meerburg , Joel Meyers , Alex van Engelen , Yacine Ali-Haïmoud

Investigation of primordial non-Gaussianity holds immense importance in testing the inflation paradigm and shedding light on the physics of the early Universe. In this study, we conduct the complete analysis of scalar-induced gravitational…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-21 Jun-Peng Li , Sai Wang , Zhi-Chao Zhao , Kazunori Kohri

In the Horndeski's most general scalar-tensor theories, we derive the three-point correlation function of scalar non-Gaussianities generated during single-field inflation in the presence of slow-variation corrections to the leading-order…

High Energy Physics - Theory · Physics 2015-06-12 Antonio De Felice , Shinji Tsujikawa

We investigate primordial non-Gaussianity in the Inflation without an Inflaton (IWI) framework, where scalar perturbations are generated at second order by primordial gravitational waves in Einstein gravity on an exact de Sitter (dS)…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-17 Mariam Abdelaziz , Marisol Traforetti , Daniele Bertacca , Raul Jimenez , Sabino Matarrese , Angelo Ricciardone

We provide a derivation from first principles of the primordial bispectrum of scalar perturbations produced during inflation driven by a canonically normalized scalar field whose potential exhibits small sinusoidal modulations. A potential…

High Energy Physics - Theory · Physics 2015-05-18 Raphael Flauger , Enrico Pajer

Several recent proposals to embed inflation into high-energy physics rely on inflationary dynamics characterized by a strongly non-geodesic motion in negatively curved field space. This naturally leads to a transient instability of…

High Energy Physics - Theory · Physics 2019-11-20 Jacopo Fumagalli , Sebastian Garcia-Saenz , Lucas Pinol , Sébastien Renaux-Petel , John Ronayne

We study cosmological tensor perturbations induced by second-order scalar perturbations in the presence of anisotropic non-Gaussianity. This class of induced tensor modes arises on superhorizon scales through the intrinsic quadrupole…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-13 Atsuhisa Ota

We present the effective field theory studies of primordial statistical anisotropies in models of anisotropic inflation. The general action in unitary gauge is presented to calculate the leading interactions between the gauge field…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-26 Tahereh Rostami , Asieh Karami , Hassan Firouzjahi

Primordial non-Gaussianity encodes vital information of the physics of the early universe, particularly during the inflationary epoch. To explore the local-type primordial non-Gaussianity $f_{\mathrm{NL}}$, we study the anisotropies in…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-25 Jun-Peng Li , Sai Wang , Zhi-Chao Zhao , Kazunori Kohri

We study primordial non-gaussianity in supersolid inflation. The dynamics of supersolid is formulated in terms of an effective field theory based on four scalar fields with a shift symmetric action minimally coupled with gravity. In the…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-07 Marco Celoria , Denis Comelli , Luigi Pilo , Rocco Rollo

In solid inflation the single field non-Gaussianity consistency condition is violated. As a result, the long tensor perturbation induces observable clustering fossils in the form of quardupole anisotropy in large scale structure power…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Mohammad Akhshik

We calculate the tensor bispectrum mediated by an excited scalar field during inflation and find that the bispectrum peaks in the squeezed configuration, which is different from that of gravitational waves induced by enhanced curvature…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-06 Zhi-Zhang Peng , Cheng-Jun Fang , Zong-Kuan Guo

We study non-Gaussianities in the primordial perturbations in single field inflation where there is radiation era prior to inflation. Inflation takes place when the energy density of radiation drops below the value of the potential of a…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-30 Suratna Das , Subhendra Mohanty

I will discuss to what degree the cosmic microwave background (CMB) can be used to constrain primordial non-Gaussianity involving one tensor and two scalar fluctuations, focusing on the correlation of one $B$-mode polarization fluctuation…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-18 P. Daniel Meerburg