Construction of The Energy–Momentum Tensor in Lattice Gauge Theory: Gradient Flow Method

Abstract

When we do not use or do not know a regularization that preserves a preferred symmetry, the construction of the Noether current composite operator corresponding to that symmetry is quite non-trivial. Such a situation occurs for the construction of the energy–momentum tensor in lattice gauge theory, because the lattice structure explicitly breaks the translational invariance. In this article, I explain a completely new approach to this problem on the basis of the gradient flow, a certain deformation of the gauge theory along a fictitious time according to diffusion-type equations.