Recent content by aiaiaial

Is A x B = | i j k | also true for Spherical Coordinates? | r1 theta1 phi1 | | r2 theta2 phi2 | Or I have to convert them to Cartesian Coordinates and do the cross product and then...

I found a solution : ) just start with ξ = (a+ + a-) * sqrt(mw/2h) and keep dealing with (a+)φ and (a-)φ.

how to compute <n|ξ^4|n>? The problem is above I guess the ladder operator becomes some very ugly term. There should be a trick to compute <n|ξ^4|n>. Could anyone tell me?

@ZetaOfThree i know the answer should be this But the question is "how to derive that", our class have finished Griffiths Electrodynamics chapter 12 (relativity in electrodynamics) and now doing chapter 8 (conservation law). I really don't know where to get started. @ZetaOfThree

The problem statement is: Assuming that we are in vacuum, and that the only work done between mechanical systems and electricity and magnetism comes from the Lorentz force, give a full, relativistic derivation of the Maxwell stress-energy tensor.