- #1
Dixanadu
- 254
- 2
Hey guys,
So I have the stress energy tensor written as follows in my notes for the complex Klein-Gordon field:
[itex]T^{\mu\nu}=(\partial^{\mu}\phi)^{\dagger}(\partial^{\nu}\phi)+(\partial^{\mu}\phi)(\partial^{\nu}\phi^{\dagger})-\mathcal{L}g^{\mu\nu}[/itex]
Then I have the next statement that [itex]T^{0i}[/itex] is given by
[itex]T^{0i}=-[(\partial_{t}\phi)^{\dagger}\nabla^{i}\phi+(\partial_{t}\phi)\nabla^{i}\phi^{\dagger}][/itex]
And I was wondering how this comes about. I can sort of see what's happened here. Obviously you replace mu and nu with 0 and i respectively to split the spatial and time derivatives. However I have a couple of questions:
1) is it true that [itex]\partial^{t}\phi=-\partial_{t}\phi[/itex]?
2) why does the Lagrangian density at the end, [itex]\mathcal{L}g^{\mu\nu}[/itex] drop out?
Thanks a lot guys :)
So I have the stress energy tensor written as follows in my notes for the complex Klein-Gordon field:
[itex]T^{\mu\nu}=(\partial^{\mu}\phi)^{\dagger}(\partial^{\nu}\phi)+(\partial^{\mu}\phi)(\partial^{\nu}\phi^{\dagger})-\mathcal{L}g^{\mu\nu}[/itex]
Then I have the next statement that [itex]T^{0i}[/itex] is given by
[itex]T^{0i}=-[(\partial_{t}\phi)^{\dagger}\nabla^{i}\phi+(\partial_{t}\phi)\nabla^{i}\phi^{\dagger}][/itex]
And I was wondering how this comes about. I can sort of see what's happened here. Obviously you replace mu and nu with 0 and i respectively to split the spatial and time derivatives. However I have a couple of questions:
1) is it true that [itex]\partial^{t}\phi=-\partial_{t}\phi[/itex]?
2) why does the Lagrangian density at the end, [itex]\mathcal{L}g^{\mu\nu}[/itex] drop out?
Thanks a lot guys :)