Belinfante–Rosenfeld stress–energy tensor

In mathematical physics, the Belinfante–Rosenfeld tensor is a modification of the energy–momentum tensor that is constructed from the canonical energy–momentum tensor and the spin current so as to be symmetric yet still conserved.

In a classical or quantum local field theory, the generator of Lorentz transformations can be written as an integral

of a local current

Here ${\displaystyle {T^{\mu }}_{\lambda }}$ is the canonical Noether energy–momentum tensor, and ${\displaystyle {S^{\mu }}_{\nu \lambda }}$ is the contribution of the intrinsic (spin) angular momentum. Local conservation of angular momentum

...
Wikipedia