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Supersymmetric hybrid inflation is an exquisite framework to connect inflationary cosmology to particle physics at the scale of grand unification. Ending in a phase transition associated with spontaneous symmetry breaking, it can naturally…

High Energy Physics - Phenomenology · Physics 2014-07-31 Wilfried Buchmuller , Valerie Domcke , Kohei Kamada , Kai Schmitz

We study multifield contributions to the scalar power spectrum in an ensemble of six-field inflationary models obtained in string theory. We identify examples in which inflation occurs by chance, near an approximate inflection point, and we…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Liam McAllister , Sébastien Renaux-Petel , Gang Xu

Thermal inflation was proposed as a mechanism to dilute the density of cosmological moduli. Thermal inflation is driven by a complex scalar field possessing a large vacuum expectation value and a very flat potential, called a `flaton'. Such…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-13 Robert Brandenberger , Aline Favero

In this lecture I will review the present status of inflation within string-based brane-world scenarios. The idea is to start from a supersymmetric configuration with two parallel static Dp-branes, and slightly break the supersymmetry…

Astrophysics · Physics 2007-05-23 Juan Garcia-Bellido

We show that a moduli space of the form predicted by string theory, lifted by supersymmetry breaking, gives rise to successful inflation for large regions of parameter space without any modification or fine tuning. This natural realization…

High Energy Physics - Phenomenology · Physics 2009-11-10 Kenji Kadota , Ewan D. Stewart

Supersymmetry breaking close to the scale of grand unification can explain cosmic inflation. As we demonstrate in this paper, this can be achieved in strongly coupled supersymmetric gauge theories, such that the energy scales of inflation…

High Energy Physics - Phenomenology · Physics 2018-06-26 Valerie Domcke , Kai Schmitz

Cosmological inflation and topological defects have been considered for a long time, either in disagreement or in competition. On the one hand an inflationary era is required to solve the shortcomings of the hot big bang model, while on the…

High Energy Physics - Theory · Physics 2008-11-26 Mairi Sakellariadou

We explore the possibility that a multiple-stage inflationary scenario based on supersymmetric GUT models, can account for the break at $k_b \simeq 0.05 h/Mpc$ in the power spectrum of galaxy clustering, while it reproduces the angular…

High Energy Physics - Phenomenology · Physics 2009-10-31 Mairi Sakellariadou

In these lectures, I review the current status of cosmic strings and cosmic superstrings. I first discuss topological defects in the context of Grand Unified Theories, focusing in particular in cosmic strings arising as gauge theory…

High Energy Physics - Theory · Physics 2009-10-06 Mairi Sakellariadou

The dynamics of a universe dominated by a self-interacting nonminimally coupled scalar field are considered. The structure of the phase space and complete phase portraits are given. New dynamical behaviors include superinflation…

General Relativity and Quantum Cosmology · Physics 2009-10-31 E. Gunzig , A. Saa , L. Brenig , V. Faraoni , T. M. Rocha Filho , A. Figueiredo

We review efforts in string model building, focusing on the heterotic orbifold compactifications. We survey how one can, starting from an explicit string theory, obtain models which resemble Nature. These models exhibit the standard model…

High Energy Physics - Theory · Physics 2024-01-09 Saul Ramos-Sanchez , Michael Ratz

Two extensions of ideas lying in the basis of the inflationary scenario of the early Universe and their effect on the large scale structure of the present-day Universe are discussed. The first of them is the possibility of fast phase…

Astrophysics · Physics 2007-05-23 A. A. Starobinsky

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

Recent developments in inflation model building, based on supersymmetry, have produced compelling models in which strings are produced at the end of inflation. In such models the cosmological perturbations are seeded both by the defects and…

Astrophysics · Physics 2009-10-31 Joao Magueijo , Carlo Contaldi , Mark Hindmarsh

At its very beginning, the universe is believed to have grown exponentially in size via the mechanism of inflation. The almost scale-invariant density perturbation spectrum predicted by inflation is strongly supported by cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-23 David F. Chernoff , S. -H. Henry Tye

The cosmological implication of a double inflation model with hybrid + new inflations in supergravity is studied. The hybrid inflation drives an inflaton for new inflation close to the origin through supergravity effects and new inflation…

High Energy Physics - Phenomenology · Physics 2009-10-31 Toshiyuki Kanazawa , M. Kawasaki , Naoshi Sugiyama , T. Yanagida

The theory of cosmological perturbations is the main tool which connects theories of the early universe (based on new fundamental physics such as string theory) with cosmological observations. In these lectures, I will provide an…

High Energy Physics - Theory · Physics 2015-06-26 Robert H. Brandenberger

We briefly discuss constraints on supersymmetric hybrid inflation models and examine the consistency of brane inflation models. We then address the implications for inflationary scenarios resulting from the strong constraints on the cosmic…

High Energy Physics - Theory · Physics 2014-10-28 Mairi Sakellariadou

Inflationary scenarios motivated by the Minimal Supersymmetric Standard Model (MSSM) where five scalar fields are non-minimally coupled to gravity are considered. The potential of the model and the function of non-minimal coupling are…

High Energy Physics - Phenomenology · Physics 2018-06-01 M. N. Dubinin , E. Yu. Petrova , E. O. Pozdeeva , S. Yu. Vernov

We show that it is possible to combine an early phase of String Gas Cosmology which can explain the origin of the observed structures on cosmological scales with a short later period of power law inflation which creates spatial flatness.…

High Energy Physics - Theory · Physics 2020-05-20 Vahid Kamali , Robert Brandenberger