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Related papers: Fluctuations in strongly coupled cosmologies

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The influence of the observed relict vacuum energy on the fluctuations of CMBR going through cosmological matter condensations is studied in the framework of the Einstein-Strauss-de Sitter vakuola model. It is shown that refraction of light…

General Relativity and Quantum Cosmology · Physics 2016-08-16 Z. Stuchlík , J. Schee

High parton densities in ultra-relativistic nuclear collisions suggest a description of these collisions wherein the high energy nuclear wavefunctions and the initial stages of the nuclear collision are dominated by classical fields. This…

Nuclear Theory · Physics 2015-05-28 Kevin Dusling , Francois Gelis , Raju Venugopalan

In this paper, we consider the Universe at the late stage of its evolution and deep inside the cell of uniformity. At these scales, we consider the Universe to be filled with dust-like matter in the form of discretely distributed galaxies,…

General Relativity and Quantum Cosmology · Physics 2016-10-05 Alvina Burgazli , Alexander Zhuk , João Morais , Mariam Bouhmadi-López , K. Sravan Kumar

This is the first paper in a series where we study collisions of nucleated bubbles taking into account the effects of small initial (quantum) fluctuations in a fully 3+1-dimensional setting. In this paper, we consider the evolution of…

High Energy Physics - Theory · Physics 2017-11-09 Jonathan Braden , J. Richard Bond , Laura Mersini-Houghton

Enhancements of primordial curvature fluctuations in single field inflation often involve departures from attractor trajectories in the phase space. We study enhancement/suppression of primordial fluctuations in one of the simplest models…

Cosmology and Nongalactic Astrophysics · Physics 2023-09-25 Guillem Domènech , Gerson Vargas , Teófilo Vargas

(abridged) We continue the study of $\Lambda$SFDM cosmologies, which differ from $\Lambda$CDM in that CDM is replaced by scalar field dark matter (SFDM) by calculating the evolution of the background Universe, as well as linear…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-16 Horst Foidl , Tanja Rindler-Daller

The quantum model of homogeneous and isotropic universe filled with the uniform scalar field is considered. This model predicts effective inverse square-law dependence of the mean total energy density <\rho> on the expectation value of…

Astrophysics · Physics 2007-05-23 V. E. Kuzmichev , V. V. Kuzmichev

( to appear in: Proceedings of the Nishonomiya Yukawa Memorial Symposium Edited by M. Sasaki) There are several models for generating fluctuations in an open universe that are compatible with the microwave background fluctuations detected…

Astrophysics · Physics 2009-09-25 David N. Spergel , Ue-Li Pen , Marc Kamionkowski , Naoshi Sugiyama

The amplitude of cosmological density fluctuations, sigma_8, has been studied and estimated by analysing many cosmological observations. The values of the estimates vary considerably between the various probes. However, different estimators…

Cosmology and Nongalactic Astrophysics · Physics 2010-02-19 Roman Juszkiewicz , Hume A. Feldman , J. N. Fry , Andrew H. Jaffe

The cosmic large-scale structure of our Universe is comprised of baryons and cold dark matter (CDM). Yet it is customary to treat these two components as a combined single-matter fluid with vanishing pressure, which is justified only for…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-04 Cornelius Rampf , Cora Uhlemann , Oliver Hahn

The possibility of thermally induced initial density perturbations in inflationary cosmology is examined. The fluctuation dynamics of a scalar field plus thermal bath system during slow roll is described by a Langevin-like equation.…

Astrophysics · Physics 2016-08-30 Arjun Berera , Li-Zhi Fang

Cosmological scalar fields coupled to the Standard Model drive temporal variations in the fundamental constants that grow with redshift, positioning the early Universe as a powerful tool to study such models. We investigate the dynamics and…

High Energy Physics - Phenomenology · Physics 2025-08-04 Masha Baryakhtar , Olivier Simon , Zachary J. Weiner

The cosmological scalar perturbations should satisfy the thermal distribution at the beginning of inflation since the cosmic temperature is presumably very high. In this paper, we investigate, by the Fubini-study method, the effect of this…

General Relativity and Quantum Cosmology · Physics 2022-12-06 Jincheng Wang , Hongwei Yu , Puxun Wu

It is assumed that the dark energy observed today is frozen as a result of a phase transition involving the source of that energy. Postulating that the dark energy de-coherence which results from this phase transition drives statistical…

Astrophysics · Physics 2009-11-10 James V. Lindesay , H. Pierre Noyes , E. D. Jones

The spatial and temporal noise properties of diffuse radiation is investigated in the context of the cosmic microwave background (CMB), although generic formulae that enable application to any other forms of incoherent light of a prescribed…

Cosmology and Nongalactic Astrophysics · Physics 2009-06-02 Richard Lieu , Bizhu Jiang

We calculate the evolution of a low-mass ($M \le 10^5 M_{\odot}$) spherically symmetric density perturbation in the $\Omega_b h^2=0.02$, $\Omega_M =0.35$, $\Omega_{\Lambda}=0.65$, $h=0.72$ Universe. The results are compared with the ones…

Astrophysics · Physics 2009-11-07 Slawomir Stachniewicz , Marek Kutschera

A well-known problem of the $\Lambda$CDM model is the tension between the relatively high level of clustering, as quantified by the parameter $\sigma_8$, found in cosmic microwave background experiments and the smaller one obtained from…

Cosmology and Nongalactic Astrophysics · Physics 2019-01-04 Bruno J. Barros , Luca Amendola , Tiago Barreiro , Nelson J. Nunes

It is shown that the fluctuation in the temperature of the cosmic microwave background in any direction may be evaluated as an integral involving scalar and dipole form factors, which incorporate all relevant information about acoustic…

Astrophysics · Physics 2009-11-06 Steven Weinberg

In cosmological models where local cosmic strings are formed at the end of a period of inflation, the perturbations are seeded both by the defects and by the quantum fluctuations. In a subset of these models, for example those based on…

Astrophysics · Physics 2009-10-30 Carlo Contaldi , Mark Hindmarsh , Joao Magueijo

We report on constraints to the cosmological jerk parameter ($j$) and to possible variability of the fine-structure constant ($\Delta \alpha/\alpha$) based on stochastic quintessence models of dark energy, discussed by Chongchitnan and…

Cosmology and Nongalactic Astrophysics · Physics 2016-03-23 Christine C. Dantas , Andre L. B. Ribeiro