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Effects of heavy fields on primordial spectra of curvature perturbations are discussed in inflationary models with a sudden turning trajectory. When heavy fields are excited after the sudden turn and oscillate around the bottom of the…

High Energy Physics - Theory · Physics 2014-03-26 Toshifumi Noumi , Masahide Yamaguchi

We study the primordial bispectrum of curvature perturbation in the uniform- density slicing generated by the interaction between the inflaton and isotropic background gauge fields. We derive the action up to cubic order in perturbation and…

Cosmology and Nongalactic Astrophysics · Physics 2013-06-05 Hiroyuki Funakoshi , Kei Yamamoto

We study the amplification of the curvature perturbations due to a small sound speed and find that its origin is different completely from that due to the ultraslow-roll inflation. This is because when the sound speed is very small the…

General Relativity and Quantum Cosmology · Physics 2022-09-20 Rongrong Zhai , Hongwei Yu , Puxun Wu

We identify a characteristic pattern in the scalar-induced stochastic gravitational wave background from particle production during inflation. If particle production is sufficiently efficient, the scalar power spectrum exhibits…

Cosmology and Nongalactic Astrophysics · Physics 2021-09-24 Jacopo Fumagalli , Sébastien Renaux-Petel , Lukas T. Witkowski

The statistical properties of the primordial density perturbations has been considered in the past decade as a powerful probe of the physical processes taking place in the early universe. Within the inflationary paradigm, the properties of…

General Relativity and Quantum Cosmology · Physics 2015-06-15 Gabriel Leon , Daniel Sudarsky

We discuss the possibility that we could obtain some hints of the heavy physics during inflation by analyzing local features of the primordial bispectrum. A heavy scalar field could leave large signatures in the primordial spectra through…

Cosmology and Nongalactic Astrophysics · Physics 2013-06-25 Ryo Saito , Yu-ichi Takamizu

Features in the primordial power spectrum require numerical methods that are both accurate and scalable across the wide class of multifield inflationary models that produce them. Sharp turns in the background trajectories, induced by either…

General Relativity and Quantum Cosmology · Physics 2026-03-31 Guillermo F. Quispe Peña , Johor D. Peñalba Quispitupa , José T. Gálvez Ghersi

Features in the primordial scalar power spectrum provide a possible roadway to describe the outliers at the low multipoles in the WMAP data. Apart from the CMB angular power spectrum, these features can also alter the matter power spectrum…

Cosmology and Nongalactic Astrophysics · Physics 2013-03-04 Dhiraj Kumar Hazra

Primordial black holes (PBHs) can be produced by a range of mechanisms in the early universe. A particular formation channel that connects PBHs with inflationary phenomenology invokes enhanced primordial curvature perturbations at small…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-06 Philippa S. Cole , Andrew D. Gow , Christian T. Byrnes , Subodh P. Patil

We show that in absence of entropy or effective anisotropic stress the freedom in the choice of the initial energy scale of inflation implies the existence of an infinite family of dual slow-roll parameters histories which can produce the…

Cosmology and Nongalactic Astrophysics · Physics 2019-04-17 Alexander Gallego Cadavid , Antonio Enea Romano

It is well known that damped superimposed oscillations at large scales in the primordial power spectrum can be generated in both single field and two field models. In single field inflationary models, these features typically arise due to…

Cosmology and Nongalactic Astrophysics · Physics 2023-10-27 Anvy Moly Tom , Rathul Nath Raveendran

The effect of spatial curvature on primordial perturbations is controlled by $ \Omega_{K,0}/c_{s}^{2} $, where $ \Omega_{K,0} $ is today's fractional density of spatial curvature and $ c_{s} $ is the speed of sound during inflation. Here we…

Cosmology and Nongalactic Astrophysics · Physics 2020-03-04 Guus Avis , Sadra Jazayeri , Enrico Pajer , Jakub Supeł

The simplest inflationary models present us with few observable parameters to discriminate between them. A detection of features in the spectra of primordial density perturbations could provide valuable insights and lead to stringent tests…

Cosmology and Nongalactic Astrophysics · Physics 2015-01-14 J. R. Fergusson , H. F. Gruetjen , E. P. S. Shellard , M. Liguori

We report on a novel phenomenon of the resonance effect of primordial density perturbations arisen from a sound speed parameter with an oscillatory behavior, which can generically lead to the formation of primordial black holes in the early…

Cosmology and Nongalactic Astrophysics · Physics 2018-08-27 Yi-Fu Cai , Xi Tong , Dong-Gang Wang , Sheng-Feng Yan

We study the generation of a localized peak in the primordial spectrum of curvature perturbations from a transient dissipative phase during inflation, leading to a large population of primordial black holes. The enhancement of the power…

Cosmology and Nongalactic Astrophysics · Physics 2024-02-16 Guillermo Ballesteros , Marcos A. G. García , Alejandro Pérez Rodríguez , Mathias Pierre , Julián Rey

We investigate the formation of large peaks in the inflationary curvature power spectrum from double-well potentials. In such scenarios, the initial CMB spectrum is created at large field values. Subsequently, the inflaton will cross one of…

Cosmology and Nongalactic Astrophysics · Physics 2023-09-06 Alexandros Karam , Niko Koivunen , Eemeli Tomberg , Antonio Racioppi , Hardi Veermäe

We study features in the bispectrum of the primordial curvature perturbation correlated with the reconstructed primordial power spectrum from the observed cosmic microwave background temperature data. We first show how the bispectrum can be…

Cosmology and Nongalactic Astrophysics · Physics 2017-12-25 Stephen Appleby , Jinn-Ouk Gong , Dhiraj Kumar Hazra , Arman Shafieloo , Spyros Sypsas

Cosmological $\alpha$-attractors stand out as particularly compelling models to describe inflation in the very early universe, naturally meeting tight observational bounds from cosmic microwave background (CMB) experiments. We investigate…

Cosmology and Nongalactic Astrophysics · Physics 2022-06-22 Laura Iacconi , Hooshyar Assadullahi , Matteo Fasiello , David Wands

We consider the pertubative consistency of inflationary models with features with effective field theory methods. By estimating the size of one-loop contributions to the three-point function, we find the energy scale where their…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-02 Dario Cannone , Nicola Bartolo , Sabino Matarrese

The primordial bispectrum has been considered in the past decade as a powerful probe of the physical processes taking place in the early Universe. Within the inflationary paradigm, the properties of the bispectrum are one of the keys that…

General Relativity and Quantum Cosmology · Physics 2015-03-09 Gabriel Leon , Daniel Sudarsky