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We study loop corrections in the effective field theory of inflation with imaginary speed of sound, which has been shown to provide an effective description of multi-field inflationary models characterized by strongly non-geodesic motion…

High Energy Physics - Theory · Physics 2025-11-14 Sebastian Garcia-Saenz , Yizhou Lu , Sébastien Renaux-Petel

We study linear scalar perturbations in single-field models of inflation featuring a non-attractor phase. These models lead to a peak in the curvature power spectrum that may result in the formation of primordial black holes. We develop a…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-26 Vadim Briaud , Alexandros Karam , Niko Koivunen , Eemeli Tomberg , Hardi Veermäe , Vincent Vennin

We re-examine the importance of slow-roll corrections during the evolution of cosmological perturbations in models of multi-field inflation. We find that in many instances the presence of light degrees of freedom leads to situations in…

Cosmology and Nongalactic Astrophysics · Physics 2012-02-28 Anastasios Avgoustidis , Sera Cremonini , Anne-Christine Davis , Raquel H. Ribeiro , Krzysztof Turzynski , Scott Watson

The decrease of both the rolling speed of the inflaton and the sound speed of the curvature perturbations can amplify the curvature perturbations during inflation so as to generate a sizable amount of primordial black holes. In the…

General Relativity and Quantum Cosmology · Physics 2024-01-17 Rongrong Zhai , Hongwei Yu , Puxun Wu

In a recent paper [17], we studied the evolution of the background geometry and scalar perturbations in an inflationary, spatially closed Friedmann-Lema\^itre-Robertson-Walker (FLRW) model having constant positive spatial curvature and…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-24 Béatrice Bonga , Brajesh Gupt , Nelson Yokomizo

Motivated by the prospect of testing inflation from precision cosmic microwave background observations, we present analytic results for scalar and tensor perturbations in single-field inflation models based on the application of uniform…

Astrophysics · Physics 2009-11-07 Salman Habib , Katrin Heitmann , Gerard Jungman , Carmen Molina-Paris

We present a complete and consistent exposition of the regularization, renormalization, and resummation procedures in the setup of having a contraction and then non-singular bounce followed by inflation with a sharp transition from…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-28 Sayantan Choudhury , Ahaskar Karde , Sudhakar Panda , Soumitra SenGupta

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 calculate 1-loop corrections to the Schwinger-Keldysh propagators of Standard-Model-like fields of spin-0, 1/2, and 1, with all renormalizable interactions during inflation. We pay special attention to the late-time divergences of loop…

High Energy Physics - Theory · Physics 2016-08-16 Xingang Chen , Yi Wang , Zhong-Zhi Xianyu

Single field inflationary models that seek to greatly enhance small scale power in order to form primordial black holes predict both a squeezed bispectrum that is enhanced by this small scale power and a potentially detectable enhancement…

Cosmology and Nongalactic Astrophysics · Physics 2022-06-08 David Zegeye , Keisuke Inomata , Wayne Hu

We study one-loop corrections to the two-point correlation function of tensor perturbations in primordial cosmology induced by massless spectator matter fields. Using the Schwinger-Keldysh formalism in cosmological perturbation theory, we…

General Relativity and Quantum Cosmology · Physics 2020-11-02 H. S. Tan

We study corrections to the power spectra of curvature and tensor perturbations and the tensor-to-scalar ratio in single field slow roll inflation due to initial conditions imprinted by a fast-roll stage prior to slow roll. For a wide range…

Cosmology and Nongalactic Astrophysics · Physics 2014-05-22 Louis Lello , Daniel Boyanovsky

Brief periods of non-slow-roll evolution during inflation can produce interesting observable consequences, as primordial black holes, or an inflationary gravitational wave spectrum enhanced at small scales. We develop a model independent,…

High Energy Physics - Theory · Physics 2021-06-29 Gianmassimo Tasinato

In this paper we compute 1-loop corrections to the bispectrum in the decoupling limit of the Effective Field Theory of Inflation (EFToI). We regulate the divergences by employing dimensional regularization and work in $d=3+\delta$…

High Energy Physics - Theory · Physics 2024-10-11 Supritha Bhowmick , Diptimoy Ghosh , Farman Ullah

We study the generation of a large power spectrum, necessary for primordial black hole formation, within the effective theory of single-field inflation. The mechanisms we consider include a transition into a ghost-inflation-like phase and…

High Energy Physics - Theory · Physics 2022-02-02 Guillermo Ballesteros , Sebastián Céspedes , Luca Santoni

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

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

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

Inflection point inflation generically includes a deviation from slow-roll when the inflaton approaches the inflection point. Such deviations are shown to be generated by transitions between singular trajectories. The effects on the power…

High Energy Physics - Theory · Physics 2013-07-22 Sean Downes , Bhaskar Dutta

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