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The recent results on the baryon acoustic oscillations measurements from the DESI collaboration have shown tantalizing hints for a time-evolving dark energy equation of state parameter $w(z)$, with a statistically significant deviation from…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-14 George Alestas , Marienza Caldarola , Sachiko Kuroyanagi , Savvas Nesseris

Single-field models of $\alpha$-attractor quintessential inflation provide a unified picture of the two periods of early- and late-time cosmic acceleration, where both inflation and dark energy are described by a single scalar degree of…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-05 Yashar Akrami , Santiago Casas , Senwen Deng , Valeri Vardanyan

A novel approach to quintessential inflation model building is studied, within the framework of $\alpha$-attractors, motivated by supergravity theories. Inflationary observables are in excellent agreement with the latest CMB observations,…

General Relativity and Quantum Cosmology · Physics 2017-06-23 Konstantinos Dimopoulos , Charlotte Owen

In the present paper, we perform a sub-Planckian quantum mode analysis of linear cosmological perturbation in the inflaton field over a classical quasi de-Siter metric background by dynamical horizon exit (DHE) method. In this way, we probe…

General Relativity and Quantum Cosmology · Physics 2023-05-05 Arunoday Sarkar , Buddhadeb Ghosh

Assuming that inflation is followed by a phase where the energy density of the Universe is dominated by a component with a general equation of state, we evaluate the spectrum of primordial gravitational waves induced in the…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-16 Nicolás Bernal , Fazlollah Hajkarim

We briefly discuss cosmic inflation, which is the dominant paradigm for the generation of the large scale structure in the Universe and also for arranging for the initial conditions of the hot Big Bang. We then present quintessential…

High Energy Physics - Phenomenology · Physics 2024-03-01 Konstantinos Dimopoulos

Quintessential inflation utilises a single scalar field to account for the observations of both cosmic inflation and dark energy. The requirements for modelling quintessential inflation are described and two explicit successful models are…

General Relativity and Quantum Cosmology · Physics 2021-06-30 Konstantinos Dimopoulos

We investigate two classes of inflationary models, which lead to a stiff period after inflation that boosts the signal of primordial gravitational waves (GWs). In both families of models studied, we consider an oscillating scalar…

High Energy Physics - Phenomenology · Physics 2024-10-10 Chao Chen , Konstantinos Dimopoulos , Cem Eröncel , Anish Ghoshal

We construct a new model of quintessential $\alpha$ attractor inflation in conjunction with the features of non-oscillating early dark energy (EDE). Slow-roll plateau of this model is obtained, and analyzed in $k$-space, through the…

General Relativity and Quantum Cosmology · Physics 2024-04-15 Arunoday Sarkar , Buddhadeb Ghosh

We study relic gravitational waves in the paradigm of quintessential inflation. In this framework, irrespective of the underlying model, inflation is followed by the kinetic regime. Thereafter, the field energy density remains sub-dominant…

General Relativity and Quantum Cosmology · Physics 2017-09-27 Safia Ahmad , R. Myrzakulov , M. Sami

Recently, attempts have been made to understand the apparent near coincidence of the present dark energy and matter energy in terms of a dynamical attractor-like solution for the evolution of a scalar field. In these models the field…

Astrophysics · Physics 2009-11-06 M. Yahiro , G. J. Mathews , K. Ichiki , T. Kajino , M. Orito

The possibility of linking inflation and late cosmic accelerated expansion using the $\alpha$-attractor models has received increasing attention due to their physical motivation. In the early universe, $\alpha$-attractors provide an…

Cosmology and Nongalactic Astrophysics · Physics 2018-08-21 Carlos García-García , Eric V. Linder , Pilar Ruíz-Lapuente , Miguel Zumalacárregui

An exponential kind of quintessential inflation potential motivated by supergravity is studied. This type belongs to the class of {\alpha}-attractor models. The model was studied for the first time by Dimopoulos and Owen in [J. Cosmol.…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-01 Llibert Aresté Saló , David Benisty , Eduardo I. Guendelman , Jaume de Haro

Models of cosmic inflation generically predict a weak but potentially detectable amount of primordial non-Gaussianity (PNG), which can be used to obtain insights into the degrees of freedom during inflation and their interactions. The…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-05 Anton Chudaykin , Mikhail M. Ivanov , Oliver H. E. Philcox

Due to universality and attractor properties, $\alpha$-attractor quintessential inflation establishes direct relations between inflationary observables such as the scalar tilt $n_s$ and the tensor-to-scalar ratio $r$, and late-time dark…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-26 William Giarè , Eleonora Di Valentino , Eric V. Linder , Enrico Specogna

The $\alpha$-attractor inflationary models are nowadays favored by CMB Planck observations. Their similarity with canonical quintessence models motivates the exploration of a common framework that explains both inflation and dark energy. We…

Cosmology and Nongalactic Astrophysics · Physics 2019-07-18 Carlos García-García , Pilar Ruíz-Lapuente , David Alonso , M. Zumalacárregui

We consider the space-condensate inflation model to study the primordial gravitational waves generated in the early Universe. We calculate the energy spectrum of gravitational waves induced by the space-condensate inflation model for full…

General Relativity and Quantum Cosmology · Physics 2016-04-27 Seoktae Koh , Bum-Hoon Lee , Gansukh Tumurtushaa

We reconsider the enhancement of primordial gravitational waves that arises from a quantum gravitational model of inflation. A distinctive feature of this model is that the end of inflation witnesses a brief phase during which the Hubble…

General Relativity and Quantum Cosmology · Physics 2015-05-30 Maria G. Romania , N. C. Tsamis , R. P. Woodard

Cosmic acceleration manifested in the early universe as inflation, generating primordial gravitational waves detectable in the cosmic microwave background (CMB) radiation. Cosmic acceleration is occurring again at present as dark energy,…

Cosmology and Nongalactic Astrophysics · Physics 2023-09-12 Tilek Zhumabek , Mikhail Denissenya , Eric V. Linder

We construct a model of quintessential inflation in Palatini $R^2$ gravity employing a scalar field with a simple exponential potential and coupled to gravity with a running non-minimal coupling. At early times, the field acts as the…

General Relativity and Quantum Cosmology · Physics 2022-11-03 Konstantinos Dimopoulos , Alexandros Karam , Samuel Sánchez López , Eemeli Tomberg
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