First-order phase transitions in finite systems can be defined through the bimodality of the distribution of the order parameter. This definition is equivalent to the one based on the inverted curvature of the thermodynamic potential. Moreover we show that it is in a one-to-one correspondence...

The general conditions for the existence of a negative heat capacity branch in nonextensive finite systems are reviewed. Partial energy fluctuations are proposed as a directly measurable observable of such a phenomenon in Gibbs as well as Tsallis equilibria.

We define a first-order phase transition as a bimodality of the event distribution in the space of observations and we show that this is equivalent to a curvature anomaly of the thermodynamical potential and that it implies the Yang Lee behavior of the zeroes of the partition sum. Moreover, it...