  In peripheral heavy ion collisions, the Quark-Gluon Plasma that may be formed
often has a large angular momentum per unit energy. This angular momentum may
take the form of (local) rotation. In many physical systems, rotation can have
effects analogous to those produced by a magnetic field; thus, there is a risk
that the effects of local rotation in the QGP might be mistaken for those of
the large genuine magnetic fields which are also known to arise in these
systems. Here we use the gauge-gravity duality to investigate this, and we find
indeed that, with realistic parameter values, local rotation has effects on the
QGP (at high values of the baryonic chemical potential) which are not only of
the same kind as those produced by magnetic fields, but which can in fact be
substantially larger. Furthermore, the combined effect of rotation and
magnetism is to change the shape of the main quark matter phase transition line
in an interesting way, reducing the magnitude of its curvature; again, local
rotation contributes to this phenomenon at least as strongly as magnetism.
