Exact results and open questions in first principle functional RG

Understand

Some aspects of the functional RG (FRG) approach to pinned elastic manifolds (of internal dimension $d$) at finite temperature $T>0$ are reviewed and reexamined in this much expanded version of [Europhys.

• Lett.
• {\bf 76} 457 (2006)].
• The particle limit $d=0$ provides a test for the theory: there the FRG is equivalent to the decaying Burgers equation, with viscosity $\nu \sim T$ - both being formally irrelevant.