Recent content by ogion

First point to be noted: You cannot interchange the two currents. If you could, by antisymmetry of the epsilon tensor, the expression is identically zero. The way the above makes sense is if the derivatives act on the right hand current. Now, for a static charge the only nonzero component of...

Your question is quite interesting. One direction to proceed to understand what systems have zero pressure? Another point to note - apropos Jack's comment - is that most atoms in a gas/liquid are neutral. So it can't really be electromagnetic in origin. If you have a gas of neutrinos - which...

I think you have it right - its the zeroth law of thermodynamics. The proof of the zeroth law is complicated - because it involves showing that there is a function of the (macroscopic) thermodynamic variables which can be used to define equilibrium (this function is the temperature) starting...

Its to be expected. The set of eigenvalues of a matrix is an invariant. So, any combinations of the eigenvalues, that is invariant under permutations will also be an invariant. This generalises to arbitrary sized square matrices.