The 34th International Symposium on Lattice Field Theory (Lattice 2016)

A gauge invariant Debye mass for the complex heavy-quark potential

28 Jul 2016, 15:20

20m

Building 32 Room 1015 (Highfield Campus, University of Southampton)

Talk Nonzero Temperature and Density Nonzero Temperature and Density

Speaker

Dr Alexander Rothkopf (Institute for Theoretical Physics, Heidelberg University)

Description

The concept of a screening mass is a powerful tool to simplify the intricate physics of in-medium test charges surrounded by light charge carriers. While it has been successfully used to describe electromagnetic properties, its definition and computation in QCD is plagued by questions of gauge invariance and the presence of non-perturbative contributions from the magnetic sector. Here we present a recent alternative definition [1] of a gauge invariant Debye mass parameter following closely the original idea of Debye and Hueckel. Our test charges are a static heavy quark-antiquark pair whose complex potential and its in-medium modification can be extracted using lattice QCD [2]. By combining in a generalized Gauss-Law the non-perturbative aspects of quark binding with a perturbative ansatz for the medium effects, we succeed to describe the lattice values of Re[V] and Im[V] [3] with a single temperature dependent parameter, in turn identified with a Debye mass. We find that its behavior evaluated both in quenched QCD [4], as well as dynamical Nf=2+1 QCD [3] deviates from that in other approaches, such as hard-thermal-loop perturbation theory or from electric field correlators on the lattice. Around the phase transition e.g. its values tend to zero significantly faster than at weak-coupling. [1] Y. Burnier, A.R. Phys.Lett. B753 (2016) 232-236
[2] A.R., T. Hatsuda, S. Sasaki, Phys.Rev.Lett. 108 (2012) 162001
[3] Y.Burnier, O. Kaczmarek, A.R. Phys.Rev.Lett. 114 (2015) 082001
[4] Y.Burnier, A.R. in preparation

Presentation materials

Slides

LATTICE_ROTHKOPF_FINAL_WEB.pdf