Electrical Conductivity of Hot QCD Matter

Abstract

We study the electric conductivity of hot QCD matter at various temperatures T within the off-shell parton-hadron-string dynamics transport approach for interacting partonic, hadronic or mixed systems in a finite box with periodic boundary conditions. The response of the strongly interacting system in equilibrium to an external electric field defines the electric conductivity σ(0). We find a sizable temperature dependence of the ratio σ(0)/T well in line with calculations in a relaxation time approach for T(c)<T<2.5T(c). The ratio drops in the hadronic phase with T, shows a minimum close to T(c), and becomes approximately constant (~0.3) above ~5T(c). Our findings imply that the QCD matter even at T ≈ T(c) is a much better electric conductor than Cu or Ag (at room temperature).

Electromagnetic field and the chiral magnetic effect in the quark-gluon plasma

“…Electrical conductivity of the quark-gluon plasma at the critical temperature is σ = 5.8 MeV [39][40][41][42]. For a heavy-ion collision at γ = 100 we estimate 1/σv 2 γ 2 ∼ 3 · 10 −3 fm.…”

“…Position of the four poles at k ⊥ → 0 can be found by expanding (42), which gives three distinct solutions ω = 0 and ω = v 2 γ 2 (iσ ± σ χ ). The former corresponds to the minimum value of the lower branches, while the later to the minimum values of the upper branches.…”

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].…”

Shear viscosity η to electrical conductivity σel ratio for an anisotropic QGP

“…It is related to the soft dilepton production rate [60] and the magnetic field diffusion in the medium [61,62]. σ el helps us to compare the effective cross sections of a medium's constituents among several theories, including lattice gauge theory [45][46][47][48][49][50][51][52][53], transport models [54,55], and Dyson-Schwinger calculations [63]. It can also be computed on the lattice from the correlation function.…”

“…It is of fundamental importance for the strength of chiral magnetic effect [44], a signature of CP-violation of the strong interaction. Recently, electric conductivity has been studied by different groups [30,31,[45][46][47][48][49][50][51][54][55][56][57][58][59]. It is related to the soft dilepton production rate [60] and the magnetic field diffusion in the medium [61,62].…”