Flow equations for spectral functions at finite external momenta

TL;DR

This paper investigates the momentum-dependent spectral functions of mesons at finite temperature and density using a non-perturbative, thermodynamically consistent method based on the Functional Renormalization Group applied to the quark-meson model.

Contribution

It introduces a novel approach to compute real-time spectral functions at finite temperature and density from the FRG, preserving symmetries and thermodynamic consistency.

Findings

Momentum dependence of pion and sigma spectral functions analyzed.

Results obtained near the critical endpoint in the phase diagram.

Method successfully applied to study spectral functions at various temperatures and densities.

Abstract

In this work we study the spatial-momentum dependence of mesonic spectral functions obtained from the quark-meson model using a recently proposed method to calculate real-time observables at finite temperature and density from the Functional Renormalization Group. This non-perturbative method is thermodynamically consistent, symmetry-preserving and based on an analytic continuation from imaginary to real time on the level of the flow equations for 2-point functions. Results on the spatial-momentum dependence of the pion and sigma spectral function are presented at different temperatures and densities, in particular near the critical endpoint in the phase diagram of the quark-meson model.