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The distance between BPS branes in string theory corresponds to a flat direction in the effective potential. Small deviations from supersymmetry may lead to a small uplifting of this flat direction and to brane inflation. However, this…

High Energy Physics - Theory · Physics 2008-11-26 Jonathan P. Hsu , Renata Kallosh , Sergey Prokushkin

We study the slow-roll inflationary dynamics in a self-gravitating induced gravity braneworld model with bulk cosmological constant. For E \gg M_{5}^{3}/M^{2}_{2} we find important corrections to the four-dimensional Friedmann equation…

General Relativity and Quantum Cosmology · Physics 2009-11-10 E. Papantonopoulos , V. Zamarias

We discuss inflation in models with large extra dimensions, driven by a bulk scalar field. The brane inflaton is then a single effective field, obtained from the bulk scalar field by scaling. The self interaction terms of the effective…

High Energy Physics - Phenomenology · Physics 2008-11-26 R. N. Mohapatra , A. Pérez-Lorenzana , C. A. de S. Pires

The slow-roll approximation to inflation is ultimately justified by the presence of inflationary attractors for the orbits of the solutions of the dynamical equations in phase space. There are many indications that the inflaton field…

General Relativity and Quantum Cosmology · Physics 2011-08-11 Valerio Faraoni

We investigate the observational viability of a class of $\alpha$-attractors inflationary models in light of the most recent Cosmic Microwave Background (CMB) and Large-Scale Structure (LSS) data. By considering a double-well potential we…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-04 J. G. Rodrigues , S. Santos da Costa , J. S. Alcaniz

We present a new type of brane inflation motivated by multi-kink solitonic solutions of a scalar field in five dimensions. In the thin brane limit, we analyze a non-static configuration in which the distance between two parallel domain…

High Energy Physics - Phenomenology · Physics 2014-11-20 Kevin T. Engel

We shall investigate the inflation for the D-brane model, motivated by the modified gravity $F(\phi,T)$. This gravity has been recently introduced in the literature. The feasibility of the D-brane inflation theory in the $F(\phi,T)$-gravity…

General Relativity and Quantum Cosmology · Physics 2025-08-04 Feyzollah Younesizadeh , Davoud Kamani

We investigate anisotropic inflation within the single-field model featuring an intermediate scale factor. Our analysis reveals that the anisotropic nature of the Friedmann equations in this framework affects the slow-roll parameters, which…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-12 Maryam Roushan , Narges Rashidi , Kourosh Nozari

Within the $\alpha$-attractors framework we investigate scalar potentials with the same pole as the one featured in the kinetic term. We show that, in field space, this leads to directions without a plateau. Using this, we present a…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-26 Konstantinos Dimopoulos , Michal Artymowski

We investigate the effects of large inhomogeneities in both the inflaton field and its momentum. We find that in general, large kinetic perturbations reduce the number of e-folds of inflation. In particular, we observe that inflationary…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-13 Matthew Elley , Josu C. Aurrekoetxea , Katy Clough , Raphael Flauger , Panagiotis Giannadakis , Eugene A. Lim

The unwinding inflation mechanism is studied in a type IIB flux compactification where all moduli are stabilized using flux, non-perturbative effects, and the leading alpha' corrections of the large volume scenario. We consider the…

High Energy Physics - Theory · Physics 2017-12-14 Juan Diaz Dorronsoro , Marjorie Schillo

A simple model of quintessential inflation with the modified exponential potential exp(-\alpha \phi) [A + (\phi-\phi_0)^2] is analyzed in the braneworld context. Considering reheating via instant preheating, it is shown that the evolution…

Astrophysics · Physics 2008-11-26 M. C. Bento , R. Gonzalez Felipe , N. M. C. Santos

We formalize the Hubble slow-roll formalism for inflationary dynamics in Randall-Sundrum Type II braneworld cosmologies, defining Hubble slow-roll parameters which can be used along with the Hamilton-Jacobi formalism. Focussing on the…

Astrophysics · Physics 2009-11-10 Erandy Ramirez , Andrew R. Liddle

We extend the Randall-Sundrum(RS) model by adding a fundamental scalar field in the bulk, then study the multi-field assisted inflationary solution on brane. We will show that this model satisfies not only the observation, but also provides…

High Energy Physics - Phenomenology · Physics 2019-08-17 Yun_Song Piao , Wenbin Lin , Xinmin Zhang , Yuan-Zhong Zhang

We reexamine inflation due to a constrained inflaton in the model of a complex scalar. Inflaton evolves along a spiral-like valley of special scalar potential in the scalar field space just like single field inflation. Sub-Planckian…

High Energy Physics - Phenomenology · Physics 2015-12-02 Romy H. S. Budhi , Shoichi Kashiwase , Daijiro Suematsu

This short note emphasises a potential tension between string models of inflation based on systems of branes and antibranes and the spectrum of strings in curved space, in particular the requirement that the leading Regge trajectory extends…

High Energy Physics - Theory · Physics 2019-11-13 Joseph P. Conlon

We show that a combination of the simplest $\alpha$-attractors and KKLTI models related to Dp-brane inflation covers most of the area in the ($n_{s}$, $r$) space favored by Planck 2018. For $\alpha$-attractor models, there are discrete…

High Energy Physics - Theory · Physics 2021-10-26 Renata Kallosh , Andrei Linde

The calculation of scalar gravitational and matter perturbations during multiple-field inflation valid to first order in slow roll is discussed. These fields may be the coordinates of a non-trivial field manifold and hence have non-minimal…

High Energy Physics - Phenomenology · Physics 2007-05-23 B. J. W. van Tent , S. Groot Nibbelink

We study an effective four-dimensional theory with an action with two scalar fields minimally coupled to gravity, and with a matter action which couples to the two scalar fields via an overall field-dependent coefficient in the action. Such…

High Energy Physics - Theory · Physics 2009-11-11 Tirthabir Biswas , Robert Brandenberger , Damien A. Easson , Anupam Mazumdar

Motivated by the possibility of inflation in the cosmic landscape, which may be approximated by a complicated potential, we study the density perturbations in multi-field inflation with a random potential. The random potential causes the…

High Energy Physics - Theory · Physics 2009-04-24 S. -H. Henry Tye , Jiajun Xu , Yang Zhang
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