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Cosmological $\alpha$-attractors stand out as particularly compelling models to describe inflation in the very early universe, naturally meeting tight observational bounds from cosmic microwave background (CMB) experiments. We investigate…

Cosmology and Nongalactic Astrophysics · Physics 2022-06-22 Laura Iacconi , Hooshyar Assadullahi , Matteo Fasiello , David Wands

We analyze the simplest possible realization of the curvaton scenario, where a nearly scale-invariant spectrum of adiabatic perturbations is generated by conversion of an isocurvature perturbation generated during inflation, rather than the…

Astrophysics · Physics 2009-11-07 N Bartolo , Andrew R Liddle

We discuss nontrivial features of the large scale structure of the universe in the simplest curvaton model proposed in our paper astro-ph/9610219. The amplitude of metric perturbations in this model takes different values in different parts…

Astrophysics · Physics 2009-11-11 Andrei Linde , Viatcheslav Mukhanov

The standard model of large scale structure is considered, in which the structure originates as a Gaussian adiabatic density perturbation with a nearly scale invariant spectrum. The basic theoretical tool of cosmological perturbation theory…

Astrophysics · Physics 2007-05-23 David H Lyth , Andrew R Liddle

The spectral triple approach to noncommutative geometry allows one to develop the entire standard model (and supersymmetric extensions) of particle physics from a purely geometry stand point and thus treats both gravity and particle physics…

High Energy Physics - Theory · Physics 2010-10-27 William Nelson , Joseph Ochoa , Mairi Sakellariadou

We study the evolution of cosmological perturbations, using a hybrid approximation scheme which upgrades the weak-field limit of Einstein's field equations to account for post-Newtonian scalar and vector metric perturbations and for…

Astrophysics · Physics 2007-05-23 Carmelita Carbone , Sabino Matarrese

We consider a mimetic set up in which the mimetic scalar is coupled to a vector field. It is shown that such a field with a time-like component does not contribute to the background equations and yet produces healthy isocurvature…

General Relativity and Quantum Cosmology · Physics 2018-06-20 M. H. Abbassi , A. Jozani , H. R. Sepangi

Inflation may provide a suitable collider to probe physics at very high energies. In this paper we investigate the impact on the CMB bispectrum of higher spin fields which are long-lived on super-Hubble scales, e.g. partially massless…

Cosmology and Nongalactic Astrophysics · Physics 2018-08-30 Gabriele Franciolini , Alex Kehagias , Antonio Riotto , Maresuke Shiraishi

We study the transition form factors of the light mesons in the kinematics, where one photon is real and other is virtual. Using the dispersive approach to axial anomaly we show that the axial anomaly in this case reveals itself as a…

High Energy Physics - Phenomenology · Physics 2010-12-23 Yaroslav N. Klopot , Armen G. Oganesian , Oleg V. Teryaev

In an inflationary cosmology, the observed primoridal density perturbation could come from the quantum fluctuations of another light 'curvaton' field, rather than the inflaton. In this case, it is essential that the curvaton decays,…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Kari Enqvist , Rose N. Lerner , Olli Taanila

We investigate the evolution of cosmological perturbations in scenarios with a quintessence scalar field, both analytically and numerically. In the tracking regime for quintessence, we find the long wavelength solutions for quintessential…

Astrophysics · Physics 2009-11-06 L. R. Abramo , F. Finelli

We introduce "anamorphic" cosmology, an approach for explaining the smoothness and flatness of the universe on large scales and the generation of a nearly scale-invariant spectrum of adiabatic density perturbations. The defining feature is…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-02 Anna Ijjas , Paul J. Steinhardt

The effect of anisotropy on the statistics of a passive tracer transported by a turbulent flow is investigated. We show that under broad conditions an arbitrarily small amount of anisotropy propagates to the large scales where it eventually…

Chaotic Dynamics · Physics 2009-11-11 Antonio Celani , Agnese Seminara

If one is willing to give up the cherished hypothesis of spatial isotropy, many interesting cosmological models can be developed beyond the simple anisotropically expanding scenarios. One interesting possibility is presented by shear-free…

Cosmology and Nongalactic Astrophysics · Physics 2015-07-22 Thiago S. Pereira , Guillermo A. Mena Marugán , Saulo Carneiro

The generalization of (super)integrable Euclidean classical Hamiltonian systems to the two-dimensional sphere and the hyperbolic space by preserving their (super)integrability properties is reviewed. The constant Gaussian curvature of the…

Mathematical Physics · Physics 2019-07-16 Angel Ballesteros , Alfonso Blasco , Francisco J. Herranz

We formulate a generalisation of the blast-wave model which is suitable for the description of higher order azimuthal anisotropies of the hadron production. The model includes anisotropy in the density profile as well as an anisotropy in…

Nuclear Theory · Physics 2017-08-09 Jakub Cimerman , Boris Tomasik , Mate Csanad , Sandor Lokos

We comprehensively explore the quadratic curvaton models in the chaotic inflation. In the light of the BICEP2 result $r \approx 0.2$, all model parameters and relevant observables are computed. It is found the curvaton field value is…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 Tomohiro Fujita , Masahiro Kawasaki , Shuichiro Yokoyama

We present the first complete calculation of the curvature perturbation generated during the hybrid inflation waterfall, caused by the coupling of the waterfall field to a gauge field A whose kinetic function f^2 depends on the inflaton…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 David H. Lyth , Mindaugas Karciauskas

A simple extension of the minimal supersymmetric standard model which naturally and simultaneously solves the strong CP and mu problems via a Peccei-Quinn and a continuous R symmetry is considered. This model is supplemented with hybrid…

High Energy Physics - Phenomenology · Physics 2009-11-10 Konstantinos Dimopoulos , George Lazarides , David Lyth , Roberto Ruiz de Austri

We introduce the concepts of adiabatic (curvature) and isocurvature (entropy) cosmological perturbations and present their relevance for parameter estimation from cosmic microwave background anisotropies data. We emphasize that, while…

Astrophysics · Physics 2016-11-09 R. Trotta , R. Durrer
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