Spectral Functions from the Functional Renormalization Group

TL;DR

This paper introduces a novel method to compute spectral functions at finite temperature and density using the Functional Renormalization Group, enabling non-perturbative analysis of phase transitions in strong-interaction matter.

Contribution

It develops a thermodynamically consistent truncation to derive flow equations for two-point functions in Minkowski space, demonstrating the method with mesonic spectral functions in hot and dense matter.

Findings

Successful calculation of mesonic spectral functions in hot and dense matter

Demonstrates the feasibility of the FRG-based spectral function method

Provides a new non-perturbative tool for studying phase transitions

Abstract

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.