- #1
michael879
- 698
- 7
Can someone please walk me through (or provide a link that does) the derivation of the EM stress-energy tensor? I get all the concepts I'm just a little confused on some of the details. Basically, you have the definition of the stress energy tensor in terms of the lagrangian, and the condition that [itex]\partial_\mu T^{\mu\nu} = 0[/itex]. What you end up with is an expression that can have anything added to it as long as its derivative remains 0. This is how you generally make the stress-energy tensor symmetric. What I'm confused about is WHY it has to be symmetric, and what prevents you from adding arbitrary constants to it? Is there some condition I'm missing?