Q:

What is Extended Fisher-Kolmogorov (EFK)?

What is Extended Fisher-Kolmogorov (EFK)?
There are many references to it, but I failed to find what is actually is. Is it some kind of non-linear differential equation? Does it describe physical systems?

A:

Short answer would be:
It is a nonlinear PDE, usually stated as
$$u_t+\gamma u_{xxxx}-u_{xx}-u+u^3=0 $$
as introduced in Dee & van Sarloos' paper. Most authors like to emphasize its application in modeling of phase transitions at critical points.

