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We consider the UV-protected inflation, where the inflaton potential is obtained by quantum (one-loop) breaking of a global symmetry into a discrete symmetry. In this model, all coupling scales are sub-Planckian. This is achieved by…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-09 Cristiano Germani , Yuki Watanabe

We generalize the treatment of inflationary perturbations to deal with the non-Markovian colored noise emerging from any realistic approach to stochastic inflation. We provide a calculation of the power-spectrum of the gauge-invariant…

Astrophysics · Physics 2009-11-10 M. Liguori , S. Matarrese , M. Musso , A. Riotto

The motion of a pseudo-scalar field $X$ during inflation naturally induces a significant amplification of the gauge fields to which it is coupled. The amplified gauge fields can source characteristic scalar and tensor primordial…

Cosmology and Nongalactic Astrophysics · Physics 2016-09-21 Marco Peloso , Lorenzo Sorbo , Caner Unal

We describe new scenarios of generating curvature perturbations when inflaton (curvaton) has significant interactions. We consider a ``spot'', which arises from interactions associated with enhanced symmetric point (ESP) on the trajectory.…

High Energy Physics - Phenomenology · Physics 2010-11-30 Tomohiro Matsuda

There are hidden observables for inflation, such as features localized in position space, which do not manifest themselves when only one inflation trajectory is considered. To address this issue, we investigate inflation dynamics in a…

High Energy Physics - Theory · Physics 2012-10-02 Francis Duplessis , Yi Wang , Robert Brandenberger

We revisit the hybrid inflation model within the framework of the Grand Unified Theory (GUT), focusing on cases where the waterfall phase transition extends over several e-foldings to dilute monopoles. Considering the stochastic effects of…

High Energy Physics - Phenomenology · Physics 2024-05-16 Yuichiro Tada , Masaki Yamada

A model is developed in which the inflaton potential experiences a sudden small change in its second derivative (the effective mass of the inflaton). An exact treatment demonstrates that the resulting density perturbation has a quasi-flat…

Astrophysics · Physics 2008-12-18 Minu Joy , Varun Sahni , Alexei A. Starobinsky

We analyse the efficiency of future large scale structure surveys to unveil the presence of scale dependent features in the primordial spectrum --resulting from cosmic inflation-- imprinted in the distribution of galaxies. Features may…

Cosmology and Nongalactic Astrophysics · Physics 2018-06-04 Gonzalo A. Palma , Domenico Sapone , Spyros Sypsas

We study the production of scalar-induced gravitational waves and primordial black holes in a single-field inflation model with a localized bump or dip feature in the potential. Introducing such a localized feature temporarily decelerates…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-13 Xiang Zhang , Zhao-Huan Yu

We characterise the primordial perturbations produced due to both inflaton and curvaton fluctuations in models where the curvaton has a quadratic, cosine or hyperbolic potential, and the inflaton potential is characterised by the usual…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 José Fonseca , David Wands

Primordial non-Gaussianities from multi-field inflation are a leading target for cosmological observations, because of the possible large correlations generated between long and short distances. These signatures are captured by the local…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-31 Dong-Gang Wang , Guilherme L. Pimentel , Ana Achúcarro

We propose a "multi-stream" inflation model, which is a double field model with spontaneous breaking and restoration of an approximate symmetry. We calculate the density perturbation and non-Gaussianity in this model. We find that this…

High Energy Physics - Theory · Physics 2014-11-18 Miao Li , Yi Wang

We calculate the bispectrum of the gravitational field fluctuations generated during warm inflation, where dissipation of the vacuum potential during inflation is the mechanism for structure formation. The bispectrum is non--zero because of…

Astrophysics · Physics 2011-05-10 S. Gupta , A. Berera , A. F. Heavens , S. Matarrese

We investigate the generation of features at large scales in the primordial power spectrum (PPS) when inflation is driven by two scalar fields. In canonical single field models of inflation, these features are often generated due to…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-19 Matteo Braglia , Dhiraj Kumar Hazra , L. Sriramkumar , Fabio Finelli

The observed baryon asymmetry, as well as potentially an asymmetry in the dark matter sector, can be produced through dissipative particle production during inflation. A distinctive feature of this mechanism is the generation of matter…

Cosmology and Nongalactic Astrophysics · Physics 2014-10-29 Mar Bastero-Gil , Arjun Berera , Rudnei O. Ramos , Joao G. Rosa

We discuss a new mechanism which can be responsible for the origin of the primordial perturbation in inflationary models, the inhomogeneous DBI reheating scenario. Light DBI fields fluctuate during inflation, and finally create the density…

High Energy Physics - Theory · Physics 2015-03-17 Sheng Li

We consider the possibility of extra spinning particles during inflation, focussing on the spin-2 case. Our analysis relies on the well-known fully non-linear formulation of interacting spin-2 theories. We explore the parameter space of the…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-08 Emanuela Dimastrogiovanni , Matteo Fasiello , A. Emir Gumrukcuoglu

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 show that the shape of the inflationary landscape potential may be constrained by analyzing cosmological data. The quantum fluctuations of fields orthogonal to the inflationary trajectory may have probed the structure of the local…

Cosmology and Nongalactic Astrophysics · Physics 2018-10-18 Xingang Chen , Gonzalo A. Palma , Bruno Scheihing Hitschfeld , Spyros Sypsas

We investigate small-scale signatures of the inflationary particle content. We consider the case of a light spin-2 particle sourcing primordial gravitational waves by employing an effective field theory description. Upon allowing…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-08 Laura Iacconi , Matteo Fasiello , Hooshyar Assadullahi , David Wands