Lattice study of the electromagnetic conductivity of the quark-gluon plasma in an external magnetic field

We study the electromagnetic conductivity of QGP in a magnetic background by lattice simulations with Nf = 2 + 1 dynamical rooted 2-stout smeared staggered fermions at the physical point. We study the correlation functions of the electromagnetic currents at T = 200 , 250 MeV and use the Tikhonov approach to extract the conductivity. The conductivity is found to rise with the magnetic field in the parallel direction and to decrease in the transverse direction, giving evidence for both the chiral magnetic effect and the magnetoresistance phenomenon in QGP. We also estimate the chiral charge relaxation time in QGP.