Leo P. Kadanoff Prize Winner: Itamar Procaccia

In this lecture I will review recent work in which we developed a screening theory for describing the effect of plastic events in amorphous solids on their emergent mechanics. The suggested theory uncovered an anomalous mechanical response of amorphous solids where plastic events collectively induce distributed dipoles that are analogous to dislocations in crystalline solids. The theory was tested against various examples of amorphous solids in two- and three dimensions, including frictional and friction-less granular media and numerical models of amorphous glass. It was shown that for generic amorphous solids classical elasticity theory needs to be re-consdiered, to allow for the fundamental changes in mechamical responses, including the appearance of energent scales that modify the theory in a substantial way. We conclude by interpreting the mechanical response as the formation of non-topological distributed dipoles that have no analogue in the crystalline defects literature. Having in mind that the onset of dipole screening is reminiscent of Kosterlitz-Thouless and Hexatic transitions, the finding of dipole screening in three-dimensions is particularly novel.