Spectral Functions from the Functional Renormalization Group
  In this article we wish to present a new method to obtain spectral functions at finite temperature and density from the Functional Renormalization Group (FRG). The FRG offers a powerful non-perturbative tool to deal with phase transitions in strong-interaction matter under extreme conditions and their fluctuation properties. Based on a thermodynamically consistent truncation we derive flow equations for pertinent two-point functions in Minkowski space-time. We demonstrate the feasibility of the method by calculating mesonic spectral functions in hot and dense hadronic matter using the quark-meson model as a simple example. 
Jochen Wambach, Ralf-Arno Tripolt, Nils Strodthoff and Lorenz von   Smekal
hep-ph hep-th nucl-th