Emissivity and conductivity of parton-hadron matter

We investigate the properties of the QCD matter across the deconfinement phase transition. In the scope of the parton-hadron string dynamics (PHSD) transport approach, we study the strongly interacting matter in equilibrium as well as the out-of equilibrium dynamics of relativistic heavy-ion collisions. We present here in particular the results on the electromagnetic radiation, i.e. photon and dilepton production, in relativistic heavy-ion collisions and the relevant correlator in equilibrium, i.e. the electric conductivity. By comparing our calculations for the heavy-ion collisions to the available data, we determine the relative importance of the various production sources and address the possible origin of the observed strong elliptic flow ν₂ of direct photons. The strong ν₂ of direct photons - which is comparable to the hadronic ν₂ - in PHSD may be attributed to hadronic channels, i.e. to meson binary reactions which are not subtracted in the data. On the other hand, the strong ν₂ of the 'parent' hadrons, in turn, may stem from the interactions in the QGP. Accordingly, the presence of the QGP may show up 'indirectly' in the direct photon elliptic flow