Lattice energy-momentum tensor from the Yang-Mills gradient flow -- a simpler prescription

Understand

In a recent paper [arXiv:1403.4772], we gave a prescription how to construct a correctly-normalized conserved energy--momentum tensor in lattice gauge theory containing fermions, on the basis of the Yang--Mills gradient flow.

• In the present note, we give an almost identical but somewhat superior prescription with which one can simply set the fermion mass parameter in our formulation zero for the massless fermion.
• This feature will be useful in applying our formulation to theories in which the masslessness of the fermion is crucial, such as multi-flavor gauge theories with an infrared fixed point.