About the equivalence of Abraham's and Minkowski's electrodynamics

Abstract

The old problem of the structure of the energy-momentum tensor of a polarized and magnetized elastic medium is investigated. It is shown that the Minkowski tensor in connection with Eckart's non-symmetric tensor—if one requires that the resulting tensor be symmetric—is equal to the sum of Eckart's symmetric tensor with the Abraham tensor. Both possibilities lead to the same energy-momentum tensor for a closed system. Consequently, the dynamical equations for both combinations are identical and the possibility of distinguishing between the two tensors by observing the Abraham force [Formula: see text] is out of the question.