Electrons are the particles that carry the current in an electrical conductor.
Since all electrons have the same charge, they repel each other electrically. As simple as this sounds, it is extremely difficult to describe the detailed behavior of a gas of interacting electrons. Emery and Luther found that they could obtain an exact mathematical description of such an interacting electron gas if they considered an idealized model with only one spatial dimension, as if all the electrons were lined up in a single row. Working with their one-dimensional model, Emery and Luther discovered that the charge and spin excitations, or movements, of the electron gas act independently, as if each electron were split into fractions. Since previous theorists believed that charge and spin were collective and could never be separated, this was an amazing finding.