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Accelerated first order methods, also called fast gradient methods, are popular optimization methods in the field of convex optimization. However, they are prone to suffer from oscillatory behaviour that slows their convergence when medium…

Optimization and Control · Mathematics 2022-01-28 Teodoro Alamo , Pablo Krupa , Daniel Limon

We present primordial non-Gaussianity predictions from a new high-precision code for simulating axion-U(1) inflation on a discrete lattice. We measure the primordial scalar curvature power spectrum and bispectrum from our simulations,…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-26 Drew Jamieson , Angelo Caravano , Eiichiro Komatsu

We compute the 3-point correlation function for a general model of inflation driven by a single, minimally coupled scalar field. Our approach is based on the numerical evaluation of both the perturbation equations and the integrals which…

Astrophysics · Physics 2010-10-27 Xingang Chen , Richard Easther , Eugene A. Lim

In this work, we analyze a power-law inflationary potential enhanced with a step that can introduce features in the primordial power spectrum. We focus on the computation of the Spectral Distortions (SD) induced by these features obtained…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-27 Jorge Mastache , Wilson Barrera , Raúl Henríquez-Ortiz

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

We investigate constraints on power spectra of the primordial curvature and tensor perturbations with priors based on single-field slow-roll inflation models. We stochastically draw the Hubble slow-roll parameters and generate the…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Masahiro Kawasaki , Toyokazu Sekiguchi

We investigate the symmetry constraints on the bispectrum, i.e. the three-point correlation function of primordial density fluctuations, in slow-roll inflation. It follows from the defining property of slow-roll inflation that primordial…

High Energy Physics - Theory · Physics 2013-03-29 Koenraad Schalm , Gary Shiu , Ted van der Aalst

We present the first computation of the cosmological perturbations generated during inflation up to second order in deviations from the homogeneous background solution. Our results, which fully account for the inflaton self-interactions as…

Astrophysics · Physics 2010-04-05 V. Acquaviva , N. Bartolo , S. Matarrese , A. Riotto

The primordial power spectra of scalar and tensor perturbations during slow-roll inflation are usually calculated with the method of Bessel function approximation. For constant-roll or ultra slow-roll inflation, the method of Bessel…

General Relativity and Quantum Cosmology · Physics 2018-04-09 Zhu Yi , Yungui Gong

Optical computing has emerged as a promising candidate for real-time and parallel continuous data processing. Motivated by recent progresses in metamaterial-based analog computing [Science 343, 160 (2014)], we theoretically investigate…

Emerging Technologies · Computer Science 2017-03-16 Amir Youssefi , Farzad Zangeneh-Nejad , Sajjad AbdollahRamezani , Amin Khavasi

The slow-roll approximation is the usual starting point to study the constraints imposed on the inflaton potential parameters by the observational data. We show that, for a potential exhibiting at least two extrema and giving rise to a…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Tiago Charters , Jose P. Mimoso , Ana Nunes

We consider stochastic inflation coarse-grained using a general class of exponential filters. Such a coarse-graining prescription gives rise to inflaton-Langevin equations sourced by colored noise that is correlated in $e$-fold time. The…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-19 Rafid Mahbub , Aritra De

We employ the formalism of the effective field theory of inflation to study the effects of a sudden change in the speed of sound of the inflationary perturbations. Such an event generates a feature with high frequency oscillations both in…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-30 Minjoon Park , Lorenzo Sorbo

We discuss bispectra of single-field inflationary models described by general Lorentz invariant Lagrangians that are at most first order in field derivatives, including the fast-roll models investigated by Noller and Magueijo. Based on a…

Cosmology and Nongalactic Astrophysics · Physics 2011-12-22 Thorsten Battefeld , Jan Grieb

Modern large-scale statistical models require to estimate thousands to millions of parameters. This is often accomplished by iterative algorithms such as gradient descent, projected gradient descent or their accelerated versions. What are…

Machine Learning · Statistics 2020-03-04 Michael Celentano , Andrea Montanari , Yuchen Wu

We calculate power spectra of cosmological perturbations at high accuracy for two classes of inflation models. We classify the models according to the behaviour of the Hubble distance during inflation. Our approximation works if the Hubble…

Astrophysics · Physics 2009-11-06 Dominik J. Schwarz , Cesar A. Terrero-Escalante , Alberto A. Garcia

This paper investigates the importance of radiative corrections for first-order phase transitions, with particular focus on the bubble-nucleation rate. All calculations are done with a strict power-counting, and observables are consistently…

High Energy Physics - Phenomenology · Physics 2022-12-07 Andreas Ekstedt

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

A step feature in the inflaton potential can model a transient breakdown of slow-roll inflation. Here we generalize the step feature to include space-dependence, allowing it also to model a breakdown of homogeneity and isotropy. The…

Astrophysics · Physics 2010-04-15 Rose Lerner , John McDonald

A smooth inflaton potential is generally assumed when calculating the primordial power spectrum, implicitly assuming that a very small oscillation in the inflaton potential creates a negligible change in the predicted halo mass function. We…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-21 Luiz Felippe S. Rodrigues , Reuven Opher
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