nLab stress-energy tensor

Redirected from "energy momentum tensor".

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Idea

In a model (in theoretical physics) of gravity coupled to other fields, the energy momentum tensor or stress energy tensor T is the variation of the matter part $S_{fields}$ in the Einstein-Hilbert action with respect to the metric, $\delta S_{fields} = T \delta g$ .

It is a measure for the energy and momentum density of the matter contribution to the theory.

Since the variation of the Einstein-Hilbert action $S_{EH}$ is the Einstein tensor $G$ , the equations of motion of gravity, hence Einstein's equations assert that (up to constant prefactors)

G = T \,.

For details see there.

Last revised on February 9, 2018 at 12:02:24. See the history of this page for a list of all contributions to it.