# Trace of SEM tensor

by jfy4
Tags: tensor, trace
 P: 647 Hi, Let $T_{\alpha\beta}$ be the stress-energy momentum tensor. What does $g_{\alpha\beta}T^{\alpha\beta}$ mean? I have always thought of the Ricci tensor and the SEM as the same thing essentially, but the Ricci scalar essentially assigns a number to the curvature of the manifold, what does $T$ say? Thanks,