Functional methods
Functional methods are a group of nonperturbative methods based on different effective actions. They come in the form of systems of differential, integral or integro-differential equations. They are used in diverse fields like condensed matter, cold atoms, quantum gravity, and particle physics.
The following systems of equations are widely used examples for functional methods:
- Dyson-Schwinger equations, the equations of motion of the 1PI effective action
- Equations of motion of nPI effective actions
- The functional renormalization group
We have developed and are using DoFun, a toolkit for the derivation and handling of such equations.