We study the electric conductivity as well as the magnetic response of hot QCD matter at various temperatures $T$ and chemical potentials ${\mu }_q$ within the off-shell parton–hadron–string dynamics transport approach for interacting partonic 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 ${\sigma }_0$, whereas the response to a moderate external magnetic field defines the induced diamagnetic moment ${\mu }_L$ ($T,{\mu }_q$) as well as the spin susceptibility ${\chi }_S(T,{\mu }_q)$. We find a sizable temperature dependence of the dimensionless ratio ${\sigma }_0/T$ well in line with calculations in a relaxation time approach for $T_c<T<2.5T_c$ as well as an increase of ${\sigma }_0$ with ${\mu }_q^2/T^2$. Furthermore, the frequency dependence of the electric conductivity $\sigma \left(\Omega \right)$ shows a simple functional form well in line with results from the dynamical quasiparticle model. The spin susceptibility ${\chi }_S(T,{\mu }_q)$ is found to increase with temperature $T$ and to rise $\sim$${\mu }_q^2/T^2$ too. The actual values for the magnetic response of the QGP in the temperature range below 250 MeV show that the QGP should respond diamagnetically in actual ultrarelativistic heavy-ion collisions since the maximal magnetic fields created in these collisions are smaller than $B_c\left(T\right)$, which defines a boundary between diamagnetism and paramagnetism.

• Received 11 December 2013
• Revised 13 February 2014

DOI:https://doi.org/10.1103/PhysRevC.89.035203