Register to reply 
Trace of SEM tensor 
Share this thread: 
#1
Oct2711, 10:38 PM

P: 647

Hi,
Let [itex]T_{\alpha\beta}[/itex] be the stressenergy momentum tensor. What does [itex]g_{\alpha\beta}T^{\alpha\beta}[/itex] 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 [itex]T[/itex] say? Thanks, 


#2
Oct2711, 11:18 PM

Sci Advisor
P: 8,399

I don't know in GR, but Nordstrom's scalar gravitation, the first consistent relativistic theory of gravity, can be reformulated using the Ricci Scalar and the trace SEM. It doesn't match observation, but it's historically interesting.
See Eq 16 of http://arxiv.org/abs/grqc/0405030 


#3
Oct2811, 01:27 AM

Sci Advisor
P: 8,399

Another random fact is that CFTs and Maxwell's equations have traceless SEMs.



Register to reply 
Related Discussions  
General Tensor contraction: Trace of EnergyMomentum Tensor (Einstein metric)  Special & General Relativity  5  
Ricci Tensor and Trace  Differential Geometry  7  
Proving trace of (1,1) Tensor is a scalar  Calculus & Beyond Homework  7  
What is the trace of the secondRank tensor?  High Energy, Nuclear, Particle Physics  5  
Trace of a tensor product  Differential Geometry  8 