# Stress-energy tensor

1. Dec 30, 2009

### paweld

What is the interpretation of stress energy-tensor in general relativity.
According to General Relativity by Wald $T^{\mu\nu} u_\mu u_\nu$
is energy density (chapter 4.2) where $u_\mu$ is observer 4-veliocity.
But for isolated particle $T^{\mu\nu} = \gamma m V_\mu V_\nu$
(http://en.wikipedia.org/wiki/Stress_energy_tensor#Isolated_particle") in particle reference frame
we obtain density of energy: $m / \gamma$ and not $m$
(because $V_\mu^2=1/\gamma^2$ - it's not 4-veliocity but simpliy veliocity).

Last edited by a moderator: Apr 24, 2017
2. Dec 30, 2009

### Polyrhythmic

The stress-energy tensor contains information about energy density, momentum density and flow of momentum(force). The Einstein field equations show that it is related to the curvature of spacetime.