Collisions of Nuclei: New Ideas for Hard Probes

At the Relativistic Heavy Ion Collider (RHIC) tiny droplets of
quark-gluon plasma have been formed in high-energy collisions of nuclei. QCD jets can be used as hard probes to study the plasma. In this talk I will introduce the idea of jet chemistry measurements to complement the existing set of jet quenching observables. I will also discuss the possible effect of inhomogeneities in the fireball on jet quenching observables.