Leading Order QED Electrical Conductivity from the 3PI Effective Action

Understand

In this article we study the electrical conductivity in QED using the resummed 3PI effective action.

• We work to 3-loop order in the effective action.
• We show that the resulting expression for the conductivity is explicitly gauge invariant, and that the integral equations that resum the pinching and colinear contributions are produced naturally by the formalism.
• All leading order terms are included, without the need for any kind of power counting arguments.