TY  - JOUR
A1  - Hakk, Eman Abdel
A1  - Tawfik, Abdel Nasser
A1  - Nada, Afaf
A1  - Yassin, Hayam
T1  - Cosmic evolution of viscous QCD epoch in causal Eckart frame
T2  - Universe
N2  - 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
KW  - observational cosmology
KW  - mathematical and relativistic aspects of cosmology
KW  - quark-gluon plasma
Y1  - 2021
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/62457
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-624571
SN  - 2218-1997
VL  - 7
IS  - 5, 112
SP  - 1
EP  - 15
PB  - MDPI
CY  - Basel
ER  -