Anisotropic flows and the shear viscosity of the QGP within a transport approach

We study the build up of elliptic flow v(2) and high order harmonics vn within a transport approach at fixed shear viscosity to entropy density ratio eta/s and with initial state fluctuations. In particular we study the effect of a temperature dependent eta/s for two different beam energies: RHIC for Au+Au at root s = 200 GeV and LHC for Pb+Pb at root s = 2.76 TeV. We find that for the two different beam energies considered the suppression of the elliptic flow and of higher harmonics V-3 (PT) and V-4 (PT) due to the viscosity of the medium have different contributions coming from the cross over or QGP phase. Moreover, we discuss the correlation between the initial spatial anisotropies epsilon(n) and flow coefficients v(n). We observe that the elliptic flow v(2) is strongly correlated with initial eccentricity epsilon(2). While higher harmonics v(3) and v(4) are weakly correlated to their asymmetry measure in coordinate space epsilon(3) and epsilon(4).