Fluctuation probes of quark deconfinement

The size of the average fluctuations of the net baryon number and electric charge in a finite volume of hadronic matter differ widely between the confined and deconfined phases. We argue that these differences may be exploited as indicators of the formation of a quark-gluon plasma in relativistic heavy-ion collisions, because fluctuations created in the initial state survive until freeze-out due to the rapid expansion of the hot fireball.