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We explore the possibility of obtaining inflation in weakly coupled heterotic string theory, where the model dependent axions are responsible for driving inflation. This model can be considered as a certain extrapolation of…

High Energy Physics - Theory · Physics 2010-10-27 Martin E. Olsson

We propose a scalar potential of inflation, motivated by modular invariant supergravity, and compute the angular power spectra of the adiabatic density perturbations that result from this model. The potential consists of three scalar…

We propose and investigate a general form of the dissipative coefficient $\Gamma=C_{\phi}T^{m}/\phi^{m-1}$ in warm inflation. We focus on discussing the strong dissipative processes $r=\Gamma/3H\gg1$ in the thermal state of approximate…

High Energy Physics - Phenomenology · Physics 2010-04-15 Yi Zhang

In this paper, we present quantitative constraints on the scalar field potential for a general class of inflationary models. (1) We first consider the reconstruction of the inflationary potential for given primordial density fluctuation…

Astrophysics · Physics 2009-10-22 Fred C. Adams , Katherine Freese

We describe a simple class of cosmological models called $\alpha$ attractors, which provide an excellent fit to the latest Planck data. These theories are most naturally formulated in the context of supergravity with logarithmic Kahler…

Cosmology and Nongalactic Astrophysics · Physics 2015-04-29 Renata Kallosh , Andrei Linde

We consider inflationary models with the inflaton coupled to the Gauss-Bonnet term assuming a special relation $\delta_1=2\lambda\epsilon_1$ between the two slow-roll parameters $\delta_1$ and $\epsilon_1$. For the slow-roll inflation, the…

General Relativity and Quantum Cosmology · Physics 2018-10-19 Zhu Yi , Yungui Gong , Mudassar Sabir

We investigate the dynamics of the recently proposed model of assisted inflation. In this model an arbitrary number of scalar fields with exponential potentials evolve towards an inflationary scaling solution, even if each of the individual…

Astrophysics · Physics 2016-08-25 Karim A. Malik , David Wands

We quantify the degree of fine tuning required to achieve an observationally viable period of inflation in the strongly dissipative regime of warm inflation. The ``fine-tuning'' parameter $\lambda$ is taken to be the ratio of the change in…

General Relativity and Quantum Cosmology · Physics 2023-04-03 Gabriele Montefalcone , Vikas Aragam , Luca Visinelli , Katherine Freese

We perform an analysis of models of chaotic inflation where the inflaton field $\phi$ is coupled non-minimally to gravity via $\xi \phi^n g^{\mu\nu}R_{\mu\nu}(\Gamma), n>0$. We focus on the Palatini theory of gravity, i.e. the case where…

General Relativity and Quantum Cosmology · Physics 2018-04-20 Laur Järv , Antonio Racioppi , Tommi Tenkanen

We study (p)reheating in alpha-attractor T-models of inflation, taking into account both scalar fields present in these models: the inflaton and the spectator. The two-field model has a negative field-space curvature which, at the end of…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-04 Tomasz Krajewski , Krzysztof Turzyński , Michał Wieczorek

We study inflation in the framework of $f(T)$-gravity in the presence of a canonical scalar field. After reviewing the basic equations governing the background cosmology in $f(T)$-gravity, we turn to study the cosmological perturbations and…

General Relativity and Quantum Cosmology · Physics 2016-02-02 K. Rezazadeh , A. Abdolmaleki , K. Karami

We derive an $\alpha=1/3$ - attractor potential of slow-roll inflation in the geometric set-up of three intersecting $D7$ branes under $T^6/Z_N$ type of $CY_3$-compactification within type IIB/F theory with some near-conifold regions. The…

High Energy Physics - Theory · Physics 2024-05-01 Arunoday Sarkar , Buddhadeb Ghosh

In this paper the scalar-tensor theory of gravity is assumed to describe the evolution of the universe and the gravitational scalar $\phi$ is ascribed to play the role of inflaton. The theory is characterized by the specified coupling…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Mian Wang

The reconstruction of a k-essence inflationary universe, considering the unification between the swampland criteria and the attractor given by the scalar spectral index $n_S(N)$ together with the slow roll parameter $\epsilon(N)$in terms of…

General Relativity and Quantum Cosmology · Physics 2021-01-01 Ramon Herrera

We present an explicit cosmological model where inflation and dark energy both could arise from the dynamics of the same scalar field. We present our discussion in the framework where the inflaton field $\phi$ attains a nearly constant…

High Energy Physics - Theory · Physics 2008-11-26 Ishwaree P. Neupane

It is likely that the Higgs potential of the Standard Model is unstable, turning negative at $\phi < \Lambda \sim 10^{10}$ GeV. Here we consider whether it is possible to have Higgs Inflation on the positive stable region of the potential…

High Energy Physics - Phenomenology · Physics 2023-09-14 John McDonald

We consider two classes of non-minimally coupled inflation models; those with a quadratic coupling of the inflaton to gravity, and the `Universal Attractor' models where the coupling is connected to the potential. We make a detailed…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 David C. Edwards , Andrew R. Liddle

We provide an update on five relatively well motivated inflationary models in which the inflaton is a Standard Model singlet scalar field. These include i) the textbook quadratic and quartic potential models but with additional couplings of…

High Energy Physics - Phenomenology · Physics 2016-04-28 Nobuchika Okada , Vedat Nefer Şenoğuz , Qaisar Shafi

The Atacama Cosmology Telescope (ACT) has recently reported updated measurements of the scalar spectral index $n_s$, revealing a tension with the predictions of many conventional inflationary models. In this work, we adopt a…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-13 Zhu Yi , Xingzhi Wang , Qing Gao , Yungui Gong

Minimal chaotic models of D-term inflation predicts too large primordial tensor perturbations. Although it can be made consistent with observations utilizing higher order terms in the K\"ahler potential, expansion is not controlled in the…

High Energy Physics - Theory · Physics 2016-05-13 Kazunori Nakayama , Ken'ichi Saikawa , Takahiro Terada , Masahide Yamaguchi