From non-interacting to interacting picture of thermodynamics and transport coefficients for quark gluon plasma

Abstract

We have attempted to build first some simplified model to map the interaction of quarks and gluons, which can be contained by their thermodynamical quantity like entropy density, obtained from calculation of lattice quantum chromo dynamics (LQCD). With respect to entropy density of the standard non-interacting massless quark gluon plasma (QGP), its interacting values from LQCD simulation are reduced as we go from higher to lower temperature through the cross-over of quark-hadron phase transition. By parameterizing increasing degeneracy factor or increasing interaction-fugacity or decreasing thermal width of quarks and gluons with temperature, we have matched LQCD data.Using that interaction picture, shear viscosity and electrical conductivity are calculated. For getting nearly perfect fluid nature of QGP, interaction might have some role when we consider temperature dependent thermal width.

Effect of magnetic field on jet transport coefficient $\hat{q}$

“…For mapping LQCD thermodynamics, we will follow the steps of Ref. [35], which is attempted to map LQCD thermodynamics of Refs. [36,37].…”

“…A rich QCD interaction in non-perturbative domain is responsible for this suppression and it is LQCD calculation that provides useful insights in this domain, where pQCD does not work well. One can map this temperature (T ) dependent suppression of P (T ), (T ), s(T ) [35] by imposing a temperature dependent fraction g(T ), multiplied with the total degeneracy factor of QGP. So, this picture assumes that as we go from high temperature to low temperature, the degeneracy factor of massless QGP system is gradually reduced.…”

“…One can find a similar kind of picture where LQCD values of different thermodynamical quantities always saturate around smaller values than their corresponding SB limits or leading order pQCD values. This equivalence between LQCD thermodynamics and jet quenching parameter is coming through the concept of temperature dependent degeneracy factor [35]. So, either by using Eq.…”

“…Following Ref. [27], firstly we have attempted to map the transition from q0 to qN through a quasi-particle type description [35], based on lattice QCD (LQCD) thermodynamics [36,37]. Latter it is extended for finite magnetic field picture based on the LQCD magneto-thermodynamics [38,39].…”

“…Acknowledgment: The authors acknowledge to few members of TPRC-IITBH -Sarthak Satapathy, Jayanta Dey, Anki Anand, Ranjesh Kumar, Ankita Mishra, Prasant Murmu, who worked on quasi-particle picture [35,58]…”