Cutoff effects on energy-momentum tensor correlators in lattice gauge theory

Abstract

We investigate the discretization errors affecting correlators of the energy-momentum tensor T μν at finite temperature in SU(N c) gauge theory with the Wilson action and two different discretizations of T μν. We do so by using lattice perturbation theory and non-perturbative Monte-Carlo simulations. These correlators, which are functions of Euclidean time x 0 and spatial momentum p, are the starting point for a lattice study of the transport properties of the gluon plasma. We find that the correlator of the energy ∫d 3xT 00 has much larger discretization errors than the correlator of momentum ∫d 3xT 0k. Secondly, the shear and diagonal stress correlators (T 12 and T kk) require N τ ≥ 8 for the x 0 = 1/2 point to be in the scaling region and the cutoff effect to be less than 10%. We then show that their discretization errors on an anisotropic lattice with a σ/a τ = 2 are comparable to those on the isotropic lattice with the same temporal lattice spacing. Finally, we also study finite p correlators. © SISSA 2009.