The electron self-energy in QED at two loops revisited

Understand

We reconsider the two-loop electron self-energy in quantum electrodynamics.

• We present a modern calculation, where all relevant two-loop integrals are expressed in terms of iterated integrals of modular forms.
• As boundary points of the iterated integrals we consider the four cases $p^2=0$, $p^2=m^2$, $p^2=9m^2$ and $p^2=\infty$.
• The iterated integrals have $q$-expansions, which can be used for the numerical evaluation.