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A generic form of low-energy effective action of superstring theories with one-loop quantum correction is well known. Based on this action we derive the complete perturbation equations and general analytic solutions in the cosmological…

Astrophysics · Physics 2009-10-31 J. Hwang , H. Noh

Cosmological correlators from inflation are often generated at tree level and hence loop contributions are bounded to be small corrections by perturbativity. Here we discuss a scenario where this is not the case. Recently, it has been shown…

High Energy Physics - Theory · Physics 2023-11-08 Mang Hei Gordon Lee , Ciaran McCulloch , Enrico Pajer

In this work, we analytically calculate the spectra of primordial perturbations at the end of Type III hilltop inflation models under the slow-roll approximation. We examine the one-loop corrections of the spectra and find that those from…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-04 Chia-Min Lin , Da-Shin Lee

We study the cancellation of quantum corrections on the superhorizon curvature perturbations from subhorizon physics beyond the single-clock inflation from the viewpoint of the cosmological soft theorem. As an example, we focus on the…

High Energy Physics - Theory · Physics 2024-01-24 Yuichiro Tada , Takahiro Terada , Junsei Tokuda

In this paper we consider realistic model of inflation embedded in the framework of loop quantum cosmology. Phase of inflation is preceded here by the phase of a quantum bounce. We show how parameters of inflation depend on the initial…

General Relativity and Quantum Cosmology · Physics 2010-04-06 Jakub Mielczarek

In numerical calculations of the primordial power spectrum of perturbations produced during inflation, for very little wavenumber $k$s, to implement the initial conditions required of the perturbation mode functions consistently, we must…

Astrophysics · Physics 2007-05-23 Ding-fang Zeng , Yi-hong Gao

We compute the full one-loop corrections to the primordial tensor power spectrum in an inflationary scenario with a non-minimally coupled spectator field, using the in-in formalism. We derive semi-analytic results for the scalar-sourced…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-14 Zhe Li , Chen Yuan , Qing-Guo Huang

Loop corrections to primordial correlation functions are unavoidable due to the non-linear nature of gravity. Previous works have established a robust framework for computing the renormalised one-loop power spectra of scalar and tensor…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-13 Matteo Braglia , Sebastián Céspedes , Lucas Pinol

Computations of quantum corrections to the CMB spectrum and to scalar field dynamics during inflation very often take advantage of the "semi-classical" approach, where the metric fluctuations are simply omitted. On the other hand, a…

High Energy Physics - Phenomenology · Physics 2015-11-04 Matti Herranen , Asgeir Osland , Anders Tranberg

Recently, several papers have claimed that superhorizon curvature perturbations are not conserved at the one-loop level in single-field inflation models if there is a transient ultra-slow-roll period. In this work, we point out that the…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-03 Keisuke Inomata

We find several missing one-loop-order contributions in previous considerations about secondary gravitational waves induced at nonlinear order in cosmological perturbations. We consider a consistent perturbative expansion to third-order in…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-03 Chao Chen , Atsuhisa Ota , Hui-Yu Zhu , Yuhang Zhu

In the inflationary scenario of loop quantum cosmology in the presence of inverse-volume corrections, we give analytic formulas for the power spectra of scalar and tensor perturbations convenient to compare with observations. Since…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-18 Martin Bojowald , Gianluca Calcagni , Shinji Tsujikawa

After introducing gauge-invariant cosmological perturbation theory we give an improved set of governing equations for multiple fluids including energy transfer. Having defined adiabatic and entropic perturbations we derive the…

Astrophysics · Physics 2007-05-23 Karim A. Malik

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

We study loop corrections to correlation functions of inflationary perturbations. Previous calculations have found that the two-point function can have a logarithmic running of the form log(k/mu), where k is the wavenumber of the…

High Energy Physics - Theory · Physics 2010-12-09 Leonardo Senatore , Matias Zaldarriaga

Precise cosmological data from WMAP and forthcoming CMB experiments motivate the study of the quantum corrections to the slowroll inflationary parameters.We find the quantum (loop) corrections to the equations of motion of the classical…

Astrophysics · Physics 2009-11-10 D. Boyanovsky , H. J. de Vega , N. G. Sanchez

In the inflationary cosmology it occurs frequently that the inflaton field is trapped in a local, transient minimum with non-zero vacuum energy. The difficulty regarding the curvature perturbation produced during such a stage is that…

Astrophysics · Physics 2009-06-23 Jinn-Ouk Gong , Misao Sasaki

We calculate the action and the interaction Hamiltonians to all orders in perturbation theory in the model of single field inflation with a transient ultra slow-roll phase. Employing the formalism of EFT of inflation, we obtain a compact…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-15 Hassan Firouzjahi , Bahar Nikbakht

We initiate a systematic study of precision calculation of the inflation correlators at the 1-loop level, starting in this paper with bosonic 1-loop bispectrum with chemical-potential enhancement. Such 1-loop processes could lead to…

High Energy Physics - Phenomenology · Physics 2022-03-02 Lian-Tao Wang , Zhong-Zhi Xianyu , Yi-Ming Zhong

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
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