Vertex corrections to the conductivity

Polaritons are quasiparticles emerging from the coupling of light to materials. The arguably best known polariton is the exciton. It consists of one electron and one hole generated through the impact of light and glued together by the Coulomb attraction. In the precessing project, a new polariton, coined p-ton, was discovered by serendipity in theoretical calculations. It consists of two electons and 2 holes that are connected to the incoming and outgoing light and glued together by magnetic or charge fluctuations that alternate in a checkerboard form. This checkerboard pattern can also be described by a change of the angle p from site to site, hence the name. The current project aims at better understanding the physics of p- tons and to lay the foundation to detect p-tons in experiment.