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We develop a general formalism for analyzing linear perturbations in multiple-field cosmological inflation based on the gauge-ready approach. Our inflationary model consists of an arbitrary number of scalar fields with non-minimal kinetic…

Astrophysics · Physics 2009-11-13 Joydev Lahiri , Gautam Bhattacharya

It is tempting to inflate along one of the many flat directions that arise in supersymmetric theories. The required flatness of the potential to obtain sufficient inflation and to not overproduce density fluctuations occurs naturally.…

High Energy Physics - Phenomenology · Physics 2009-10-28 Katherine Freese , Tony Gherghetta , Hideyuki Umeda

We calculate power spectra of cosmological perturbations at high accuracy for two classes of inflation models. We classify the models according to the behaviour of the Hubble distance during inflation. Our approximation works if the Hubble…

Astrophysics · Physics 2009-11-06 Dominik J. Schwarz , Cesar A. Terrero-Escalante , Alberto A. Garcia

In loop quantum cosmology, the universe avoids a big bang singularity and undergoes an early and short super-inflation phase. During super-inflation, non-perturbative quantum corrections to the dynamics drive an inflaton field up its…

Astrophysics · Physics 2011-02-23 Shinji Tsujikawa , Parampreet Singh , Roy Maartens

We consider the effective evolution of a phenomenological model from FLRW supersymmetric quantum cosmology with a scalar field. The scalar field acts as a clock and inflaton. We examine a family of simple superpotentials that produce an…

General Relativity and Quantum Cosmology · Physics 2022-08-17 N. E. Martínez-Pérez , C. Ramírez , V. M. Vázquez Báez

The cosmological solutions of the non-minimal $ Y (R)F^2 $ theory which are compatible with FRW space-time are investigated. In order to avoid the isotropy violation of a vector field, it can be considered that the presence of a triplet of…

General Relativity and Quantum Cosmology · Physics 2019-12-24 Özcan Sert

We construct non-linear inflaton potential energy densities that describe not-necessarily very-slowly-rolling closed and open inflation models, and compute tilted primordial spatial inhomogeneity power spectra that follow from quantum…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-02 Bharat Ratra

Inflation creates large-scale cosmological density perturbations that are characterized by an isotropic, homogeneous, and Gaussian random distribution about a locally flat background. Even in a flat universe, the spatial curvature measured…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Matthew Kleban , Marjorie Schillo

After reviewing the motivations for cosmological inflation formulated in the formalism of supersymmetry, we argue that the appropriate framework is that of no-scale supergravity. We then show how to construct within this framework…

High Energy Physics - Phenomenology · Physics 2021-02-24 John Ellis , Marcos A. G. Garcia , Natsumi Nagata , Dimitri V. Nanopoulos , Keith A. Olive , Sarunas Verner

In this talk we discuss three different issues. First of all, there exist several proposals how to solve cosmological problems by adiabatic expansion of the Universe, without any use of inflation. We explain why these models do not solve…

Astrophysics · Physics 2007-05-23 Andrei Linde

In this article, we review how strong dynamics can be efficiently employed as a viable alternative to study the mechanism of cosmic inflation. We examine single-field inflation in which the inflaton emerges as a bound state stemming from…

High Energy Physics - Phenomenology · Physics 2015-02-03 Phongpichit Channuie

We consider several classes of noncommutative inflationary models within an extended version of patch cosmological braneworlds, starting from a maximally invariant generalization of the action for scalar and tensor perturbations to a…

High Energy Physics - Theory · Physics 2009-11-10 Gianluca Calcagni

The end of inflation is connected to the standard cosmological scenario through reheating. During reheating, the inflaton oscillates around the minimum of the potential and thus decays into the daughter particles that populate the Universe…

General Relativity and Quantum Cosmology · Physics 2016-10-19 R. Kabir , A. Mukherjee , D. Lohiya

The intermediate, logamediate and exponential inflationary models in the context of Galileon inflation or G-inflation are studied. By assuming a coupling of the form $G(\phi,X)\propto\phi^{\nu}\,X^{n}$ in the action, we obtain different…

General Relativity and Quantum Cosmology · Physics 2018-12-05 Ramon Herrera , Nelson Videla , Marco Olivares

The cosmological constant problem is how one chooses, without fine-tuning, one singular point $\Lambda_{eff}=0$ for the 4D cosmological constant. We argue that some recently discovered {\it weak self-tuning} solutions can be viewed as…

High Energy Physics - Theory · Physics 2009-11-07 Jihn E. Kim

We study the cosmological inflation within the context of f(Q, T) gravity, wherein Q is the nonmetricity scalar and T is the trace of the matter energy-momentum tensor. By choosing a linear combination of Q and T, we first analyze the…

General Relativity and Quantum Cosmology · Physics 2022-08-30 Maryam Shiravand , Saeed Fakhry , Mehrdad Farhoudi

Inflation has been the driving idea in cosmology for two decades and is a pillar of the New Cosmology. The inflationary paradigm has now passed its first round of significant tests, with two of its three basics predictions confirmed at…

Astrophysics · Physics 2014-10-13 Michael S. Turner

In this article, we explore the concept of cosmological inflation within the framework of the $f (T,\mathcal{T})$ theory of gravity, where $f$ is a general function of the Torsion scalar $T$ and the trace, $\mathcal{T}$, of the…

General Relativity and Quantum Cosmology · Physics 2023-11-14 Aaqid Bhat , Sanjay Mandal , P. K. Sahoo

We propose a mechanism for generating an inflationary phase in the early universe without resorting to any type of scalar field(s). Instead, this accelerated expansion is driven by a dynamical "cosmological constant" in the framework of…

General Relativity and Quantum Cosmology · Physics 2022-03-18 Gabriel Leon

We derive an expression for the non-Gaussian cosmic-microwave-background (CMB) statistic $I_l^3$ defined recently by Ferreira, Magueijo, and G\'orski in terms of the slow-roll-inflation parameters $\epsilon$ and $\eta$. This result shows…

Astrophysics · Physics 2011-02-02 Limin Wang , Marc Kamionkowski