  Heavy-quark observables in ultrarelativistic heavy-ion collisions, like the
nuclear modification factor and the elliptic flow, give insight into the
mechanisms of high-momentum suppression and low-momentum thermalization of
heavy quarks. Here, we present a global study of these two observables within a
coupled approach of the heavy-quark propagation in a realistic fluid dynamical
medium, MC@sHQ+EPOS2, and compare to experimental data from RHIC and LHC
experiments. The heavy quarks scatter elastically and inelastically with the
quasiparticles of the quark-gluon plasma (QGP), which are represented
consistently with the underlying equation of state. We examine two scenarios:
first, we interpret the lattice QCD equation of state as a sum of partonic and
hadronic contributions, and second, as a gas of massive partonic
quasiparticles. It is observed that independent of their momentum the energy
loss of heavy quarks depends strongly on how the lattice QCD equation of state
is translated into degrees of freedom of the QGP.
