Transport coefficients from the Nambu–Jona-Lasinio model for SU(3)f

Abstract

We calculate the shear η(T ) and bulk viscosities ζ (T ) as well as the electric conductivity σ e (T ) and heat conductivity κ(T ) within the Nambu-Jona-Lasinio model for three flavors as a function of temperature as well as the entropy density s(T ), pressure P(T ) and speed of sound c 2 s (T ). We compare the results with other models such as the Polyakov-Nambu-Jona-Lasinio (PNJL) model and the dynamical quasiparticle model (DQPM) and confront these results with lattice QCD data whenever available. We find the NJL model to have a limited predictive power for the thermodynamic variables and various transport coefficients above the critical temperature whereas the PNJL model and DQPM show acceptable results for the quantities of interest.

Bulk viscosity for pion and nucleon thermal fluctuation in the hadron resonance gas model

“…Some of them [2,4,5] indicated divergence tendency of ζ/s near transition temperature, some of effective QCD model cal-culations [22][23][24]27] revealed peak structure near transition temperature, whereas most of the effective QCD model calculations [20,21,25,27,28] as well as effective hadronic model calculations [32,[34][35][36][37], including our present work, predict a decreasing function of ζ/s(T ) in the hadronic temperature domain, with few exceptional HRG calculations [33,36]. Our decreasing ζ/s(T, µ B = 0) is representing a strongly coupled picture in the hadronic temperature domain, whose smooth extrapolation to high temperature domain agrees with a weakly coupled picture [19].…”

“…A list of references are [2,[19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37], where Ref. [19] addressed high temperature perturbative QCD calculations of ζ, Refs.…”

“…[26][27][28] provided the discussions on Linear Sigma Model (LSM) estimation of ζ. These effective QCD model calculations [20][21][22][23][24][25][26][27][28] cover both QGP and hadronic phases while hadronic-model calculations of Refs. [32][33][34][35][36][37] are restricted within hadronic phase only.…”

“…[19] addressed high temperature perturbative QCD calculations of ζ, Refs. [20][21][22][23][24][25] have gone through Nambu-Jona-Lasinio (NJL) model calculations of ζ and Refs. [26][27][28] provided the discussions on Linear Sigma Model (LSM) estimation of ζ.…”

Temperature dependent transport coefficients in a dynamical holographic QCD model

“…For example, due to the strong electric field created in the collision region, electric conductivity is now becoming more and more interesting [49,50]. The electric conductivity describes the response of the system to external electric field and is responsible for the production of the collective flow of charged particles [51].…”