- #1
TerryW
Gold Member
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- Homework Statement
- Show that the Trace of the Heat Flux Stress/Energy Tensor is zero
- Relevant Equations
- T(heat) = q^i u^j + u^i q^j
I'm pretty sure I understand why q^i u^j + u^i q^i is the stress component (i \neq j) of the Heat Flux Stress/Energy Tensor but I can't think of, or find any explanation for why q^i u^i + u^i q^i = 0.
I found one reference in Lightman, Press, Price and Teukolsky - Problem Book in Relativity and Gravitation which just says
"Since q^α u_α = 0 (heat flux is spacelike in comoving frame)" but what does that really mean from a physics point of view?
Can anyone help?TerryW
PS - Preview doesn't seem to be working at the moment
I found one reference in Lightman, Press, Price and Teukolsky - Problem Book in Relativity and Gravitation which just says
"Since q^α u_α = 0 (heat flux is spacelike in comoving frame)" but what does that really mean from a physics point of view?
Can anyone help?TerryW
PS - Preview doesn't seem to be working at the moment
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