  We study the rotational collective motion of the quark-gluon plasma in
relativistic heavy ion collisions using the widely-adopted AMPT (A Multi-Phase
Transport) model. The global angular momentum, the average vorticity carried by
the quark-gluon plasma, and the locally defined vorticity fields are computed
for Au+Au collisions, with detailed information of their time evolution,
spatial distribution, as well as the dependence on beam energy and collision
centrality.
