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We analytically compute the power spectrum of primordial curvature perturbations in Type III hilltop inflation models under the slow-roll approximation. The model parameters are constrained using current Cosmic Microwave Background (CMB)…

General Relativity and Quantum Cosmology · Physics 2024-11-28 Chia-Min Lin , Harish Dhananjay Nalla , Chen-Pin Yeh , Da-Shin Lee

We examine the quantum loop effects on the single-field inflationary models in a spatially flat Friedmann-Robertson-Walker (FRW) cosmological space-time with a general self-interacting scalar field potential, which is modeled in terms of…

General Relativity and Quantum Cosmology · Physics 2020-02-05 Wei-Can Syu , Da-Shin Lee , Kin-Wang Ng

We consider the dynamics of a quantum scalar field in the background of a slow-roll inflating Universe. We compute the one-loop quantum corrections to the field and Friedmann equation of motion, in both a 1PI and a 2PI expansion, to leading…

High Energy Physics - Phenomenology · Physics 2015-06-18 Matti Herranen , Tommi Markkanen , Anders Tranberg

It is known that the single-field inflation with a transient ultra-slow-roll phase can produce a large curvature perturbation at small scales for the formation of primordial black holes. In our previous work, we have considered quantum loop…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-09 Shu-Lin Cheng , Da-Shin Lee , Kin-Wang Ng

We investigate loop corrections to the primordial fluctuations in the single-field inflationary paradigm from spectator fields that experience a smooth transition of their vacuum expectation values. We show that when the phase transition…

High Energy Physics - Theory · Physics 2018-05-22 Yi-Peng Wu , Jun'ichi Yokoyama

We compute one-loop corrections to the power spectrum of the curvature perturbation in single-field slow-roll inflation arising from gravitons and inflaton interactions. The quantum corrections due to gravitons to the power spectrum of the…

Astrophysics · Physics 2011-07-13 Emanuela Dimastrogiovanni , Nicola Bartolo

We investigate the one-loop quantum correction to the power spectrum of primordial curvature perturbations in the ultra-slow-roll (USR) inflationary scenario, incorporating the backreaction effect from curvature perturbations. In the…

General Relativity and Quantum Cosmology · Physics 2025-07-30 Cheng-Jun Fang , Zhen-Hong Lyu , Chao Chen , Zong-Kuan Guo

An estimate of the one-loop correction to the power spectrum of the primordial curvature perturbation is given, assuming it is generated during a phase of single-field, slow-roll inflation. The loop correction splits into two parts, which…

Astrophysics · Physics 2010-02-09 David Seery

Primordial black holes can be formed from the collapse of large-amplitude perturbation on small scales in the early Universe. Such an enhanced spectrum can be realized by introducing a flat region in the potential of single-field inflation,…

High Energy Physics - Theory · Physics 2024-05-30 Jason Kristiano , Jun'ichi Yokoyama

We compute the primordial scalar, vector and tensor metric perturbations arising from quantum field inflation. Quantum field inflation takes into account the nonperturbative quantum dynamics of the inflaton consistently coupled to the…

Astrophysics · Physics 2009-11-11 F. J. Cao

We compute the primordial scalar, vector and tensor metric perturbations arising from quantum field inflation. Quantum field inflation takes into account the nonperturbative quantum dynamics of the inflaton consistently coupled to the…

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

In addition to generating the appropriate perturbation power spectrum, an inflationary scenario must take into account the need for inflation to end subsequently. In the context of single-field inflation models where inflation ends by…

Astrophysics · Physics 2009-11-10 Michaël Malquarti , Samuel M. Leach , Andrew R. Liddle

We revisit the one-loop correction in curvature perturbation power spectrum in models of single field inflation which undergo a phase of ultra slow-roll (USR) inflation. We include the contributions from both the cubic and quartic…

Cosmology and Nongalactic Astrophysics · Physics 2023-10-06 Hassan Firouzjahi

Loop corrections to observables in slow-roll inflation are found to diverge no worse than powers of the log of the scale factor, extending Weinberg's theorem to quasi-single field inflation models. Demanding perturbation theory be valid…

High Energy Physics - Theory · Physics 2013-05-01 Klaus Larjo , David A. Lowe

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 quantum corrections to an inflationary model, which has the attractive feature of being classically scale-invariant. In this model, quadratic gravity plays along a scalar field in such a way that inflation begins near the unstable…

General Relativity and Quantum Cosmology · Physics 2019-05-22 Silvia Vicentini , Luciano Vanzo , Massimiliano Rinaldi

We estimate large-scale curvature perturbations from isocurvature fluctuations in the waterfall field during hybrid inflation, in addition to the usual inflaton field perturbations. The tachyonic instability at the end of inflation leads to…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 José Fonseca , Misao Sasaki , David Wands

In this paper, we provide a systematic investigation of high-order primordial perturbations with nonlinear dispersion relations due to quantum gravitational effects in the framework of {\em uniform asymptotic approximations}. Because of…

General Relativity and Quantum Cosmology · Physics 2016-07-06 Tao Zhu , Anzhong Wang , Klaus Kirsten , Gerald Cleaver , Qin Sheng

We study the generation of the primordial curvature perturbation in multi-field inflation. Considering both the evolution of the perturbation during inflation and the effects generated at the end of inflation, we present a general formula…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Ki-Young Choi , Soo A Kim , Bumseok Kyae

In loop quantum cosmology, the universe avoids a big bang singularity and undergoes an early and short super-inflation phase. During super-inflation, non-perturbative quantum corrections to the dynamics drive an inflaton field up its…

Astrophysics · Physics 2011-02-23 Shinji Tsujikawa , Parampreet Singh , Roy Maartens
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