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We develop a numerical statistical method to study linear cosmological fluctuations in inflationary scenarios with multiple fields, and apply it to an ensemble of six-field inflection point models in string theory. The latter are concrete…

Cosmology and Nongalactic Astrophysics · Physics 2012-07-05 Sébastien Renaux-Petel

We discuss the principles governing the selection of inflationary models for which preheating can affect the CMB. This is a (fairly small) subset of those models which have non-negligible entropy/isocurvature perturbations on large scales…

Astrophysics · Physics 2009-11-07 Shinji Tsujikawa , Bruce A. Bassett

The dynamics of hybrid models is usually approximated by the evolution of a scalar field slowly rolling along a nearly flat valley. Inflation ends with a waterfall phase, due to a tachyonic instability. This final phase is usually assumed…

Cosmology and Nongalactic Astrophysics · Physics 2011-09-27 Sébastien Clesse

In this paper, we study the case of single field inflation within the framework of modified gravity theory where the gravity part has an arbitrary form $f(R)$. Via a conformal transformation, this case can be transformed into its Einstein…

Cosmology and Nongalactic Astrophysics · Physics 2015-04-14 Taotao Qiu , Jun-Qing Xia

It is now understood that inflation dynamics comes in two forms, isentropic or cold inflation and nonisentropic or warm inflation. In the former, inflation occurs without radiation production, whereas in the latter both radiation production…

High Energy Physics - Phenomenology · Physics 2007-05-23 Arjun Berera

Within General Relativity, a minimally coupled scalar field governed by a quadratic potential is able to produce an accelerated expansion of the universe provided its value and excursion are larger than the Planck scale. This is an…

High Energy Physics - Theory · Physics 2021-02-03 Jose D. Edelstein , Robert B. Mann , David Vázquez Rodríguez , Alejandro Vilar López

We present the first calculation of the Bayesian evidence for different prototypical single field inflationary scenarios, including representative classes of small field and large field models. This approach allows us to compare…

Cosmology and Nongalactic Astrophysics · Physics 2011-05-10 Jerome Martin , Christophe Ringeval , Roberto Trotta

During inflation, there is a preferred reference frame in which the expansion of the background spacetime is spatially isotropic. In contrast to Minkowski spacetime, observables can depend on the velocity of the system with respect to this…

General Relativity and Quantum Cosmology · Physics 2021-02-16 Tanguy Grall , Scott Melville

The amplitude of primordial curvature perturbations is enhanced when a radiation bath at a temperature T>H is sustained during inflation by dissipative particle production, which is particularly significant when a non-trivial statistical…

High Energy Physics - Phenomenology · Physics 2014-04-03 Sam Bartrum , Mar Bastero-Gil , Arjun Berera , Rafael Cerezo , Rudnei O. Ramos , Joao G. Rosa

We provide a detailed study of natural inflation with a periodic non-minimal coupling, which is a well-motivated inflationary model that admits an explicit UV completion. We demonstrate that this construction can satisfy the most recent…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-18 Alberto Salvio , Simone Sciusco

Recent LHC data provides precise values of coupling constants of the Higgs field, however, these measurements do not determine its coupling with gravity. We explore this freedom to see whether Higgs field non-minimally coupled to…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-17 Jose Mathew , S. Shankaranarayanan

We study multi-field inflation in random potentials generated via a non-equilibrium random matrix theory process. We make a novel modification of the process to include correlations between the elements of the Hessian and the height of the…

Cosmology and Nongalactic Astrophysics · Physics 2018-10-22 Sonia Paban , Robert Rosati

The possibility that the scale-invariant inflationary spectrum may be modified due to the hidden assumptions about the Planck scale physics -- dubbed as trans-Planckian inflation -- has received considerable attention. To mimic the possible…

High Energy Physics - Theory · Physics 2009-11-11 S. Shankaranarayanan , Musongela Lubo

We develop an approach for linking the power spectra, bispectrum, and trispectrum to the geometric and kinematical features of multifield inflationary Lagrangians. Our geometric approach can also be useful in determining when a complicated…

Cosmology and Nongalactic Astrophysics · Physics 2012-11-26 Courtney M. Peterson , Max Tegmark

We revisit two-field hybrid inflation as an effective field theory for low-scale inflation with sub-Planckian scalar field ranges. We focus on a prototype model by Stewart because it allows for a red spectral tilt, which still fits the…

High Energy Physics - Theory · Physics 2021-03-17 Nemanja Kaloper , Morgane König , Albion Lawrence , James H. C. Scargill

The stochastic approach aims at describing the long-wavelength part of quantum fields during inflation by a classical stochastic theory. It is usually formulated in terms of Langevin equations, giving rise to a Fokker-Planck equation for…

General Relativity and Quantum Cosmology · Physics 2019-05-22 Lucas Pinol , Sébastien Renaux-Petel , Yuichiro Tada

We perform the analysis of the trispectrum of curvature perturbations generated by the interactions characterizing a general theory of single-field inflation obtained by effective field theory methods. We find that curvature-generated…

Cosmology and Nongalactic Astrophysics · Physics 2011-01-27 Nicola Bartolo , Matteo Fasiello , Sabino Matarrese , Antonio Riotto

We propose one way to regularize the fluctuations generated during inflation, whose infrared (IR) corrections diverge logarithmically. In the case of a single field inflation model, recently, we proposed one solution to the IR divergence…

High Energy Physics - Theory · Physics 2010-02-02 Yuko Urakawa , Takahiro Tanaka

Despite the fact that experimentally with a high degree of statistical significance only a single Standard Model--like Higgs boson is discovered at the LHC, extended Higgs sectors with multiple scalar fields not excluded by combined fits of…

High Energy Physics - Phenomenology · Physics 2017-12-15 M. N. Dubinin , E. Yu. Petrova , E. O. Pozdeeva , M. V. Sumin , S. Yu. Vernov

We provide some comments about the constraints on the inflationary models inferred from the two Swampland criteria which have been recently proposed. In particular we argue that, in the absence of any knowledge about the origin of the…

High Energy Physics - Theory · Physics 2018-11-14 Alex Kehagias , Antonio Riotto