Like-charge attraction in one- and two-dimensional Coulomb systems

Abstract

The bare Coulomb interaction between two like-charges is repulsive. When these charges are immersed in an electrolyte, the thermal fluctuations of the ions turn the bare Coulomb interaction into an effective interaction between the two charges. An interesting question arises: is it possible that the effective interaction becomes attractive for like-charges? We will show how this like-charge attraction phenomenon is indeed predicted in some one- and two-dimensional models of Coulomb systems. Exact analytical results can be obtained for these Coulomb systems models due to some connections that they have with integrable field theories. We will explain the techniques that allow obtaining exact results for the correlation functions between like-charge particles and how, under certain circumstances, the natural repulsion interaction shifts to being attractive. Although the technical details differ for 1d or 2d systems, the physical cause of this phenomenon is rooted in a three-body interaction between the two like-charges and an ion of the electrolyte with an opposite charge.