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We investigate the amplification of curvature perturbations in a two-field inflation model featuring a Gaussian potential bump. When the inflaton encounters a potential bump along the inflationary trajectory, its rolling speed is generally…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-10 Chengjie Fu , Chao Chen

We study a double inflation model (a hybrid inflation + a new inflation) in supergravity and discuss the formation of primordial black holes (PBHs) with mass \sim 10^{-20}-10^{5}M_{\odot}. We find that in a wide range of parameter space, we…

High Energy Physics - Phenomenology · Physics 2008-11-26 Toshiyuki Kanazawa , M. Kawasaki , T. Yanagida

We examine the possibility of Primordial Black Holes (PBHs) formation in single-field models of inflation. Using the adiabatic or wave function renormalization scheme in the short-range modes, we show that one-loop correction to the power…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-04 Sayantan Choudhury , Mayukh R. Gangopadhyay , M. Sami

We consider the superpotential formalism to describe the evolution of scalar fields during inflation, generalizing it to include the case with non-canonical kinetic terms. We provide a characterization of the attractor behaviour of the…

High Energy Physics - Theory · Physics 2016-02-24 Jaume Garriga , Yuko Urakawa , Filippo Vernizzi

In this work, we investigate the generation of primordial black holes (PBHs) within the framework of single-field inflationary models and their compatibility with the cosmological history of the Universe. Our results suggest that, depending…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-30 Sasha Allegrini , Loris Del Grosso , Antonio J. Iovino , Alfredo Urbano

We consider a class of multi-component hybrid inflation models whose evolution may be analytically solved under the slow-roll approximation. We call it multi-brid inflation (or $n$-brid inflation where $n$ stands for the number of inflaton…

Astrophysics · Physics 2009-10-09 Misao Sasaki

We present new single field inflationary scenarios that produce the critical abundance of primordial black holes as dark matter reconstructing the inflaton potential from an input power spectrum. The method is exact in the slow roll…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-11 Gabriele Autieri , Michele Redi

In view of cosmological parameters being measured to ever higher precision, theoretical predictions must also be computed to an equally high level of precision. In this work we investigate the impact on such predictions of relaxing some of…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-23 Mindaugas Karčiauskas , Kazunori Kohri , Taro Mori , Jonathan White

We investigate the enhancement of the power spectra large enough to produce primordial black holes in models with multiple scalar fields. We present analytic solutions for the perturbations in the case of constant turns without the need for…

High Energy Physics - Theory · Physics 2024-09-12 Perseas Christodoulidis , Jinn-Ouk Gong

We propose a two-field model where the inflaton $\chi$ is non-minimally coupled to the instanton $\phi$. By choosing an appropriate coupling function, we realize the scenario where the difference of the values of potential between false…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-25 Haonan Wang , Ying-li Zhang , Teruaki Suyama

We identify the effective theory describing inflationary super-Hubble scales and show it to be a special case of effective field theories appropriate to open systems. Open systems allow information to be exchanged between the degrees of…

High Energy Physics - Theory · Physics 2015-09-01 C. P. Burgess , R. Holman , G. Tasinato , M. Williams

We extend the formalism of stochastic inflation to the setup of non-attractor inflation with a sound speed $c_s$. We obtain the Langevin equations for the superhorizon perturbations and calculate the stochastic corrections to curvature…

High Energy Physics - Theory · Physics 2020-12-09 Hassan Firouzjahi , Amin Nassiri-Rad , Mahdiyar Noorbala

Quantization implies independent degrees of freedom that do not appear in the classical theory, given by fluctuations, correlations, and higher moments of a state. A systematic derivation of the resulting dynamical systems is presented here…

High Energy Physics - Theory · Physics 2021-08-24 Martin Bojowald , Suddhasattwa Brahma , Sean Crowe , Ding Ding , Joseph McCracken

We derive analytic bounds on the shape of the primordial power spectrum in the context of single-field inflation. In particular, the steepest possible growth has a spectral index of $n_s - 1 = 4$ once transients have died down. Its primary…

Cosmology and Nongalactic Astrophysics · Physics 2019-06-24 Christian T. Byrnes , Philippa S. Cole , Subodh P. Patil

We compute the leading order connected four-point function of the primordial curvature perturbation coming from the four-point function of the fields in multi-field DBI inflation models. We confirm that the consistency relations in the…

High Energy Physics - Theory · Physics 2009-10-29 Shuntaro Mizuno , Frederico Arroja , Kazuya Koyama

In order to go beyond the mean-field approximation, commonly used in the inflationary computations, an identification of the quantum constituents of the inflationary background is made. In particular, the homogeneous scalar field…

High Energy Physics - Theory · Physics 2017-03-08 Lasha Berezhiani

We study the bispectrum of the curvature perturbation on uniform energy density hypersurfaces in models of inflation with two scalar fields evolving simultaneously. In the case of a separable potential, it is possible to compute the…

Astrophysics · Physics 2009-11-11 Filippo Vernizzi , David Wands

This study explores the realization of nonminimally coupled Higgs inflation in the context of no-scale supergravity, investigates the formation of primordial black holes, and examines the potential for observable proton decay within the…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-22 Nadir Ijaz , Maria Mehmood , Mansoor Ur Rehman

We study inflation driven by a scalar potential arising from composite-sector dynamics, inspired by generalized composite Higgs models. The introduction of a non-minimal coupling, possessing the same functional form as the potential,…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-01 Marco Merchand

Cosmological perturbations, originating in the quantum fluctuations of the fields that drive inflation, are observed to be nearly scale invariant at the largest scales. At smaller scales, however, perturbations are not severely constrained…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-09 Ioannis Dalianis