2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/138110We briefly summarize the properties of conserved charge fluctuations as a sensitive probe for the QCD phase transitions. We discuss the density fluctuations which play a significant role to search for the critical end point. The importance of spinodal instabilities to distinguish the first-order phase transition is also indicated.8 pages, 5 figures; to appear in the proceedings of 4th International Workshop on Critical Point and Onset of Deconfinement, Darmstadt, Germany, 9-13 Jul 2007High Energy Physics - PhenomenologyNuclear Theorytext