What is the interpretation of stress energy-tensor in general relativity.(adsbygoogle = window.adsbygoogle || []).push({});

According to General Relativity by Wald [itex] T^{\mu\nu} u_\mu u_\nu [/itex]

is energy density (chapter 4.2) where [itex] u_\mu [/itex] is observer 4-veliocity.

But for isolated particle [itex] T^{\mu\nu} = \gamma m V_\mu V_\nu [/itex]

(http://en.wikipedia.org/wiki/Stress_energy_tensor#Isolated_particle") in particle reference frame

we obtain density of energy: [itex]m / \gamma [/itex] and not [itex]m[/itex]

(because [itex]V_\mu^2=1/\gamma^2[/itex] - it's not 4-veliocity but simpliy veliocity).

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# Stress-energy tensor

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