Cosmic evolution of viscous QCD epoch in causal Eckart frame

  • It is conjectured that in cosmological applications the particle current is not modified but finite heat or energy flow. Therefore, comoving Eckart frame is a suitable choice, as it merely ceases the charge and particle diffusion and conserves charges and particles. The cosmic evolution of viscous hadron and parton epochs in casual and non-casual Eckart frame is analyzed. By proposing equations of state deduced from recent lattice QCD simulations including pressure p, energy density ρ, and temperature T, the Friedmann equations are solved. We introduce expressions for the temporal evolution of the Hubble parameter H˙, the cosmic energy density ρ˙, and the share η˙ and the bulk viscous coefficient ζ˙. We also suggest how the bulk viscous pressure Π could be related to H. We conclude that the relativistic theory of fluids, the Eckart frame, and the finite viscous coefficients play essential roles in the cosmic evolution, especially in the hadron and parton epochs

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Author:Eman Abdel Hakk, Abdel Nasser TawfikORCiD, Afaf Nada, Hayam Yassin
Parent Title (English):Universe
Place of publication:Basel
Document Type:Article
Date of Publication (online):2021/04/21
Date of first Publication:2021/04/21
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2021/09/06
Tag:mathematical and relativistic aspects of cosmology; observational cosmology; quark-gluon plasma
Issue:5, 112
Page Number:15
First Page:1
Last Page:15
Institutes:Physik / Physik
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 53 Physik / 530 Physik
Licence (German):License LogoCreative Commons - Namensnennung 4.0