[Zurück]

N. Wentzell, C. Taranto, A. Katanin, A. Toschi, S. Andergassen:
"Correlated starting points for the functional renormalization group";
Physical Review B, 91 (2015), S. 045120-1 - 045120-11.

We present a general frame to extend functional renormalization group (fRG) based computational schemes
by using an exactly solvable interacting reference problem as starting point for the RG flow. The systematic
expansion around this solution accounts for a nonperturbative inclusion of correlations. Introducing auxiliary
fermionic fields by means of a Hubbard-Stratonovich transformation, we derive the flow equations for the
auxiliary fields and determine the relation to the conventional weak-coupling truncation of the hierarchy of flow
equations. As a specific example we consider the dynamical mean field theory (DMFT) solution as reference
system, and discuss the relation to the recently introduced DMF2RG and the dual-fermion formalism.

http://dx.doi.org/10.1103/PhysRevB.91.045120