Fluctuation of strongly interacting matter in the Polyakov-Nambu-Jona-Lasinio model in a finite volume

We estimate the susceptibilities of conserved charges for two-flavor strongly interacting matter with varying system sizes, using the Polyakov loop enhanced Nambu-Jona-Lasinio model. The susceptibilities for vanishing baryon densities are found to show a scaling with the system volume in the hadronic as well as partonic phase. This scaling breaks down for a temperature range of about 30-50 MeV around the crossover region. Simultaneous measurements of the various susceptibilities may, thus, indicate how close to the crossover region the freeze-out occurs for the fireball created in heavy-ion collision experiments.