  Simultaneous description of heavy quark nuclear suppression factor $R_{AA}$
and the elliptic flow $v_2$ is a top challenge for all the existing models. We
highlight how the temperature dependence of the energy loss/transport
coefficients is responsible to address a large part of such a puzzle along with
the the full solution of the Boltzmann collision integral for the momentum
evolution of heavy quark. We consider four different models to evaluate the
temperature dependence of drag coefficients of the heavy quark in the QGP. We
have also highlighted the heavy quark dynamics in the presence of an external
electromagnetic field which develops a sizable heavy quark directed flow,
$v_1(y)$, can be measurable at LHC.
