QCD viscosity by combining the gradient flow and sparse modeling methods

Abstract

We give a new description to obtain the shear viscosity in QCD at finite temperature. Firstly, we obtain the correlation function of the renormalized energy-momentum tensor using the gradient flow method. Secondly, we estimate the spectral function from the smeared correlation functions using the sparse modeling method. The combination of these two methods looks promising to determine the shear viscosity precisely.

Comments: 9pages, 3figures, Proceedings of The 38th International Symposium on Lattice Field Theory, LATTICE2021 26th-30th July, 2021, (ver2) Figure 1 is changed, reference is added