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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

The inflationary and pre-inflationary evolution of scalar modes of cosmological perturbations in a closed universe is analyzed for a loop quantum cosmology model with an inflationary regime consistent with the constraints on inflation…

General Relativity and Quantum Cosmology · Physics 2024-11-26 Lucas M. V. Montese , Nelson Yokomizo

Large corrections to the inflationary tensor power spectrum have been speculated to emerge either as second-order scalar-induced classical effects, or as 1-loop quantum corrections. These two sources are not independent of each other.…

High Energy Physics - Phenomenology · Physics 2026-05-28 A. Hauser , M. Laine

We discuss the possible role of isocurvature perturbations for the quantum decoherence of the curvature perturbation during inflation. We point out that if the inflaton trajectory in field space is curved, the adiabatic mode is generically…

Astrophysics · Physics 2011-08-04 Tomislav Prokopec , Gerasimos I. Rigopoulos

We express the in-in functional determinant giving the one-loop effective potential for a scalar field propagating in a cosmological spacetime in terms of the mode functions specifying the vacuum of the theory and then apply adiabatic…

General Relativity and Quantum Cosmology · Physics 2015-12-09 Ali Kaya , Emine Seyma Kutluk

Realistic models of particle physics include many scalar fields. These fields generically have nonminimal couplings to the Ricci curvature scalar, either as part of a generalized Einstein theory or as necessary counterterms for…

Cosmology and Nongalactic Astrophysics · Physics 2010-09-27 David I. Kaiser , Audrey T. Todhunter

We study multi-field Dirac-Born-Infeld (DBI) inflation models, taking into account the NS-NS and R-R bulk fields present in generic flux compactifications. We compute the second-order action, which governs the behaviour of linear…

High Energy Physics - Theory · Physics 2010-05-12 David Langlois , Sebastien Renaux-Petel , Daniele A. Steer

We perform adiabatic regularization of power spectrum in nonminimally coupled general single-field inflation with varying speed of sound. The subtraction is performed within the framework of earlier study by Urakawa and Starobinsky dealing…

General Relativity and Quantum Cosmology · Physics 2018-03-15 Allan L. Alinea , Takahiro Kubota

We expound ten principles in an attempt to clarify the debate over infrared loop corrections to the primordial scalar and tensor power spectra from inflation. Among other things we note that existing proposals for nonlinear extensions of…

Cosmology and Nongalactic Astrophysics · Physics 2012-07-04 S. P. Miao , R. P. Woodard

Current data are in good agreement with the predictions of single field inflation. However, the hemispherical asymmetry seen in the cosmic microwave background data, may hint at a potential problem. Generalizing to multi-field models may…

High Energy Physics - Theory · Physics 2015-06-15 Chris Gordon , Paul M. Saffin

We analyze the dark matter power spectrum at three-loop order in standard perturbation theory of large scale structure. We observe that at late times the loop expansion does not converge even for large scales (small momenta) well within the…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-18 Diego Blas , Mathias Garny , Thomas Konstandin

Though simple inflationary models describe the CMB well, their corrections are often plagued by infrared effects that obstruct a reliable calculation of late-time behaviour. We adapt to cosmology tools designed to address similar issues in…

General Relativity and Quantum Cosmology · Physics 2016-08-30 C. P. Burgess , R. Holman , G. Tasinato

Loop quantum cosmology (LQC) provides promising resolutions to the trans-Planckian issue and initial singularity arising in the inflationary models of general relativity. In general, due to different quantization approaches, LQC involves…

General Relativity and Quantum Cosmology · Physics 2015-12-10 Tao Zhu , Anzhong Wang , Gerald Cleaver , Klaus Kirsten , Qin Sheng , Qiang Wu

We initiate the study of multi-field inflation using holography. Bulk light scalar fields correspond to nearly marginal operators in the boundary theory and the dual quantum field theory is a deformation of a CFT by such operators. We…

High Energy Physics - Theory · Physics 2015-06-23 Jaume Garriga , Kostas Skenderis , Yuko Urakawa

We analyze the trajectories for multifield DBI inflation, which can arise in brane inflation models, and show that the trajectories are the same as in typical slow roll inflation. We calculate the power spectrum and find that the higher…

High Energy Physics - Theory · Physics 2008-11-26 Min-xin Huang , Gary Shiu , Bret Underwood

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

The recent progress in embedding inflation in string theory has made it clear that the problem of moduli stabilization cannot be ignored in this context. In many models a special role is played by the volume modulus, which is modified in…

High Energy Physics - Theory · Physics 2009-11-10 Marcus Berg , Michael Haack , Boris Kors

The era of precision cosmology has allowed us to accurately determine many important cosmological parameters, in particular via the CMB. Confronting Loop Quantum Cosmology with these observations provides us with a powerful test of the…

General Relativity and Quantum Cosmology · Physics 2012-04-06 Ivan Agullo , Abhay Ashtekar , William Nelson

We make a detailed calculation of the amplitude of isocurvature perturbations arising from inflationary models in which the cold dark matter is represented by a scalar field which acquires perturbations during inflation. We use this to…

Astrophysics · Physics 2009-10-31 Andrew R Liddle , Anupam Mazumdar

Adiabatic (curvature) perturbations are produced during a period of cosmological inflation that is driven by a single scalar field, the inflaton. On particle physics grounds -- though -- it is natural to expect that this scalar field is…

Astrophysics · Physics 2009-11-06 N. Bartolo , S. Matarrese , A. Riotto
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