# Permittivity Matrix

1. Jun 6, 2007

### Blukstak

I cant seem to demonstrate that in anisotropic materials the permittivity matrix is symmetric, apparently this is done with the poyinting vector...

I really need to understand it thanks...

2. Jun 7, 2007

### Meir Achuz

There are arguments for the symmetry of epsilon, but they tend to be circular.
This is because electromagnetic energy can ony be defined if epsilon is symmetric.