Geometrical characterization of dynamical heterogeneities in chemical gels, colloidal gels and colloidal glasses

One of the challenges in soft and condensed matter over the last years is understanding the phenomena of the glass and jamming transitions. A recent advance in the field is the idea that the dynamical heterogeneities play here the same role as the critical fluctuations in ordinary critical phenomena. This is due to the fact that the decay of density fluctuations in glasses and jammed systems takes place thanks to the dynamically correlated motions of groups of particles. In this paper, after a brief review of the properties of the dynamical heterogeneities, we describe their geometrical interpretation in chemical gels, colloidal gels and colloidal glasses, respectively, characterized by bonds with an infinite lifetime, with a finite lifetime, and by the absence of physical bonds.